I was four years old when my father came back to kidnap me. It was Sunday night, Ed Sullivan night, the TV was blasting, and I was making so much noise that we didn't hear his truck drive up. This is how my sisters tell it. Mom was next door playing calookie, Joyce was sacked out on the couch, Marcia was cross-legged on the floor, bouncing Belle in her lap. 'A really big shoe !' I was screaming at Ed's ugly mortician's face, swinging my body back and forth like a two-by-four with the arms nailed on.

When he gunned the motor I ran to the window, and seconds later the room was in chaos. My father, who had disappeared a few weeks earlier, kicked in the door and grabbed me. 'We're getting out of here,' he said, hoisting me up like I weighed nothing. I was naked to the waist and barefoot, and as we moved to the car, I felt both thrilled and terrified. Then I heard my mother screaming behind us like a cat getting skinned. 'Put him down, you son of a bitch!' she yelled, yanking me halfway out of his arms. He squeezed my wrists, she held my ankles, and they stood there pulling me apart. 'Let us go!' I pleaded with her, but she kicked him in the groin instead, dragged me to the house, and locked the door.

I ran to the window and pounded my fists. My father was doubled over by the headlights, clutching himself and rocking. Then he straightened up, slid behind the wheel and gunned the motor. He honked the horn once, then inched back out of the driveway. The headlights bounced when the truck hit the street, then disappeared slowly down the block.

I never saw or heard from my father again.

Thirty-two years later, I was sitting in a restaurant telling this story to a friend as I'd told it a hundred times before. He asked me what people always ask: why had I never looked for my father?

'He was a worthless bastard,' I said. 'I was lucky that he left.' That had been the family line, pounded into my head growing up, backed up by a list of his vices: alcohol, stealing, chasing women, lying pathologically. Besides all that, my mother was sure that I wasn't the kind of son he had wanted. I was 'sensitive,' 'artistic,' not a grease-monkey jock-type like him. She convinced me that our relationship would have been a disaster. Finally, I said to my friend, I have no interest in knowing someone who didn't want to know me. If my father gave a damn what became of me after that night in '61, he could look me up in the telephone book. I was listed.

This line always sounded convincing before, but this time it rang hollow. I could hear my own psychological scam, smell the cover-up I'd helped construct. 'We tell ourselves stories in order to live,' Joan Didion wrote years ago, and suddenly I asked myself if I hadn't done the same thing as a way of surviving abandonment. Why had I never looked for my father, really? Why hadn't I so much as thought of seeking him out on the many occasions a father is called for - bar mitzvah, graduations, funerals, career moves? Who might I have been if this man whom everyone hated was in my life today? As far back as I could remember, I had the feeling that half of me was covered in shadow, not quite real, a partial phantom. Had this darkness been cast, I wondered, by my father's absence? Could his disappearance at age 37 - the exact age I was as I sat there - be the handicap that had haunted me for so long? Was this, in fact, the reason why (in deep and troubling ways) I could not assume my own authority, balance my chequebook, sign a lease, commit to a lover, become a man?

These are the questions that prompted me seven years ago to find my father - a 69-year-old machinist and army vet named James J Matousek - dead or alive.

I met the detective, Mack Sullivan, in his office overlooking Broadway. Snowy-haired and baby-faced, Sullivan was, I'd been told, one of the best in the business. He asked me to describe in minute detail everything I knew about my father, and seemed amazed by how little that was. I had no photograph of us together, no knowledge of paternal grandparents, no birth date, no correspondence - nothing but genes and a surname to prove that Jim Matousek ever existed. Sullivan listened and took notes, and the more I told him, the redder his face became. 'I'm gonna nail this guy,' he said angrily.

'I hope so,' I said.

'In the meantime, squeeze what you can out of your mother.'

'I've tried.'

'Squeeze again.'

The detective didn't know what he was asking. My mother, Ida, is the ostrich type - no see, no hear, no en casa . Though my baby sister Belle - who was less than a year old when Jim disappeared - was thrilled at the prospect of meeting the father she never knew, Ida was adamantly against it. She told me flat out that he was dead.

'How can you be sure?' I asked her on the phone.

'I'm sure, Mark. Leave it alone.'

I told her I was doing this mostly out of curiosity - I used to be a reporter by trade - and had nearly convinced even myself that I wasn't emotionally invested in the outcome. To calm Ida down, I told her that I simply wanted to resolve this mystery, as if it were someone else's father, and close this parenthesis once and for all. She could not seem to comprehend this. As far as my mother was concerned, it was good riddance to bad rubbish - rubbish she had long ago swept into oblivion. Pressed with questions of who my father was, she responded like an amnesiac, her memory riddled with dead spots and holes.

When were you married? 'Who can remember?'

Where was the wedding? 'It was a long time ago.'

What were his parents' names? 'Never met them.'

Brothers and sisters? 'If you don't stop!'

In fact, my mother recalled nothing but the colour of my father's eyes ('grey like a wolf's'), his peptic ulcers and his habit of making paycheques disappear before she could get her hands on them.

'Why don't you really want me to find him?' I asked her, tired of dancing around the truth.

'You couldn't take it,' she said.

'Maybe I could.'

'Well, maybe I couldn't.'

So that's it, I think, the real bottom line. In spite of herself, she finally agreed to cooperate with the search by getting me a copy of their marriage certificate from the Hall of Records. When it arrived a few weeks later, I saw my father's signature for the first time -graceful, almost feminine, not nearly as rough as I would have expected - and my grandmother's maiden name, Busch.

My parents were the first couple on the block to get a divorce. JFK was still president and I was the only boy in the neighbourhood without a dad, someone to show me how to play ball, how to fix stuff, how to think of girls as other than sisters. What was a man supposed to feel like? This was the fathomless mystery. When it came to the workings of a man's heart, the instinct he'd have for finding the door and knowing how to enter the world, I was completely stumped. Without this model of masculinity, boyhood's normal confusion about sex was exaggerated for me into a sort of identity crisis. The bathroom was my laboratory, the mirror a sort of microscope for scrutinising this person I was. I used my mother's make-up kit to discover at what point I stopped being me - whoever that was - and started being someone else. Sometimes I was Genghis Khan, scowling and uni-browed, other times I turbaned my head and puckered my lips like Marilyn Monroe. Without a man within intimate range, a trunk to branch off from, a model to copy, I felt like neither boy nor girl; in fact, I felt like only half a child, as if the other part of me had stuck to my father's hands that night and disappeared with him in his car.

Lists and memos began to flood in from Mack Sullivan's office. There were documents from banks and government agencies, the Social Security Department. I was surprised by how many James Matouseks there are in the world, and how each one had some disqualifying characteristic: too young, too short, too old, too rich. Attached to the lists were cryptic notes from Sullivan, some of them so film noir they made me laugh. 'We will reach him on a ruse,' said one, regarding a Jim in California. Or: 'On 9 April, Investigator DB proceeded to the New York Public Library Annex for old phone books.' I imagined one of Sullivan's assistants slithering down Fifth Avenue in a trenchcoat, white pages strapped against his body. It all seemed very camp.

Two envelopes arrived in the post from agencies I contacted before hiring Sullivan. One, for $17.95, provided the names of seven living people with my father's name, the other with 10 who were deceased. Fortunately, none of the dead Jims had my father's middle initial. Three of the living did, however, and without telling Sullivan, I decided to call them on my own.

I dialled the one in Iowa first. An old man answered. I explained my situation and asked - feeling absolutely ridiculous - if there was any chance that he could be my father.

'I wish I could say I was,' said the old guy.

'Are you sure?' I asked, surprised by the disappointment in my voice. 'I don't want anything from you - him - except to talk.'

'I wish I could help you, but I've never lived outside of this town and never had kids. Wanna ask my wife? Milly!' he shouted before I could stop him.

'Hello?' said an old lady.

I was so embarrassed that I hung up.

I called the other two Jims and got similar results - ironclad alibis and pitying voices I was not prepared for. One of them asked me if I had any friends I could talk to. For the first time, I felt like an orphan. I wondered if I was doing the right thing, whether I should leave well enough alone. I considered calling the whole thing off.

I told my family the details when I visited them a few weeks later in California. I was amazed to find that my search had jarred their memories. Suddenly, my aunt, my sister, even my mother started revealing details about my father that I'd never known.

'Remember the first time Jim came back to get you?' my older sister Joyce asked.

'The first time?' I nearly choked, glaring at my mother fiddling intently with her cigarette.

'He locked you in a motel room and threatened not to let you out if Mommy didn't give in.' Ida rolled her eyes. 'Or the time he threw you in the crib and practically broke your neck?'

'You know what I remember?' said Aunt Ruth. 'He had a cleft in his chin like Kirk Douglas.'

'Handsome,' my mother chimed in. 'A real ladies' man.' For the first time in my life, I heard unsarcastic affection in her voice for somebody she claimed to loathe.

'Tell me the truth, Mom,' I said. 'Didn't you ever love him?'

She stared past me through the patio screen. 'Maybe, once upon a time.' She put out her smoke and lit another. 'He sure was one hell of a lover,' she said.

'Sex isn't love,' her prudish sister Ruth added quickly.

'I'll put it to you this way,' said Ida, the former bad girl who ran away from her Orthodox Jewish house to cruise with the hoodlums. 'I'd never seen that much man before in my entire life.'

Later, in bed, replaying her words, the only recollection of being alone with my father floated up into memory. We were in the shower, it was morning, and my face barely reached the top of his leg. I remembered vividly how his body looked, the strange hairy parts of him, his penis covered with soap, the distant realisation that I would look like him some day. It was just my father and I, together in this hidden place. He squirted shampoo in my hair and scrubbed my scalp hard, then pulled my face into his thigh and tickled me where I hated it, under the arms, till I fell on the floor and begged him to stop. 'Please, please!' I screamed, half-tormented, half-ecstatic. He snorted like a bull and wouldn't let up.

Then my mother was pounding on the door, yelling for us to get out. 'Don't listen to her,' my father said, turning off the water, wrapping me in a thick white towel. I sat on the toilet and watched him while he shaved. Talking to me, not paying attention, he caught the razor in the cleft of his chin and put a plaster over the blood.

Back home, I reported all this to Sullivan - excluding the shower scene. 'I told you they needed to be goosed,' he said.

He continued his paper chase with the tenacity of a pit bull. According to the Department of Health and Human Services, no death benefits had been paid on anyone with my father's name. This meant that unless he was living under an alias or foregoing his Social Security benefits, he wasn't dead.

When I grew impatient with this slow process, Sullivan suggested another tack. Apparently, Health and Human Services has a policy of helping family members track down missing relatives in emergency situations. For this to happen, I needed to write an open letter to my father which they would forward to anyone with his name. Sullivan suggested that I include a photograph of myself with the letter. I spent a day deciding what image I wanted my father to see - with hair or without - and decided finally on the balding truth. I felt a stab of ridiculous, vain regret that he hadn't know me in my halcyon days - as if he would've loved a curly-haired son more than one with a wispy monk's tonsure.

I wrote an awkward open letter (knowing it would be read by strangers), explaining that I had contracted a 'possibly fatal virus', and ending with a polite request for my father to 'contact me immediately', with no strings attached. I assured him that my mother did not need to know about our meeting. Then I sealed the envelope and sent it off to some bureaucrat in Washington DC.

Nothing happened. Two weeks passed, then four, then six. The excitement of the chase began to wane; intrigue was replaced by cynicism, then by impending defeat. My sister Belle was more disappointed than I was and wept on the telephone.

'He's never gonna see my kids,' she said, 'or even know what I look like.' Belle had become my reality check, my reminder of what was really at stake here, which my writer's distance could nearly blur out.

'It's not over yet,' I told her, barely hiding my own doubt. 'Sullivan's good. If our father's out there, he'll find him.'

'Do you even care?' Belle asked, sounding like I was a heartless wretch.

'I'm not really sure.'

In the middle of May, Sullivan called to say he was on to something. A James J Matousek with an Illinois Social Security number had turned up somewhere in California. When I pressed the detective for details, he was cagey about the suspect's exact whereabouts, and said he wanted to do 'recon naissance' before we went any further. Also, there seemed to be a hitch: the files of this guy's current account had been purged.

'Purged?' I asked. 'What does that mean?'

'Beats the hell out of me.'

It turned out that this particular suspect was last seen in Pasadena, a few minutes' drive from where my father had originally left us. In the weeks that followed, Sullivan learned that no obituary for James J Matousek had been published i n that vicinity. He charmed a librarian into researching the Mountain View Cemetery, Pasadena's most popular burial ground, but she could not find a grave. For the first time since the search began, Sullivan seemed flummoxed. 'All roads end in 1989,' he wrote to me in a memo. 'Not sure what this means, but I will continue to trace him.'

Shortly afterward, I left the city to spend the summer in Santa Fe, determined not to put my life on hold for what may end up being a wild-goose chase. I settled into a house with a view of the Sangre de Cristo mountains to work on a book, and do my best to put my father, Sullivan and the memos behind me. Thirty-two years without my father had hardened me against hope. And now, with a change of location, the prospects of finding him turned even more spectral, like the cow skull hanging above the front door.

It was a relief to have half-given up. I felt righteous for having tried and failed. Then one morning, my boyfriend Louis and I came home to a message from Mack Sullivan on the answering machine. 'Call me immediately,' he said. 'We've found him.'

From the time I was very small, I was told that I had my father's face. 'Look at him!' my older sisters would marvel. 'The profile, the way he walks. Exactly like Jim.' My mother would shake her head as if to say, 'Don't encourage him', and they'd stop.

She didn't realise how much I needed to hear this, how I needed to look like someone other than myself and Belle. Everyone in our house was fat and dark; she and I were blond and skinny, like aliens that blew in through the window and never really belonged.

Then one day while I was still in New York, my aunt Ruth called up. 'I found him!' she exclaimed. 'The movie, I mean.'

'What movie?' I asked.

'Just come out and see for yourself.'

I wangled a press trip to California, and immediately drove to Aunt Ruth's house. She put a reel on the projector, and a shaky home movie flickered on to the screen. The camera followed my mother while she rushed around in capris and a tie-up blouse, serving burgers and beers to people at a party. Then the lens zoomed in on a wavy-haired man with an angular face, T-shirt sleeves rolled up around his biceps. The man turned to the camera, smiled, and I saw, with a shock, my own face mirrored back at me.

'My God!' I said out loud, staring into my father's eyes, seeing where I'd come from for the first time in my adult life. I sat there studying my father's face, the receding hairline like mine, the sunken cheeks, long nose, deep-set melancholy eyes, hardly able to believe the chilling resemblance. It filled me with a tirade of feelings - vindication, excitement, sadness, redemption, confusion, loneliness, rage. I sat there staring a long time, memorising his face again, letting the fact of my father sink in.

'We told you, honey,' said Aunt Ruth. 'Remember?'

I called Sullivan back. 'If this isn't him, I'll turn in my licence,' he told me.

I said nothing.

'You OK?' he asked.

'I'm not sure.'

'Scared?'

'Uh huh.'

'Who wouldn't be?'

The detective told me what he knew. Apparently, Sullivan tracked down this suspect through his neighbours, who provided the unlisted phone number. Sullivan himself called 'on a ruse' and heard two names on the answering machine. 'He lives with another man,' he says. 'A foreigner.'

'Now what?' I asked.

'You call him.'

Suddenly, I felt cornered. 'What do I say?'

'Tell him you're his long-lost son. Tell him you're his pride and joy. Tell him that he ruined your life.'

'What?'

'Just kidding,' he said. 'Here's the number. Call me after you make contact.'

I couldn't do it. For 24 hours, the scrap of paper with the Pasadena phone number sat by the phone accusingly. Every time I thought about calling, I got into a panic. What had begun somewhat casually had become a little too real for comfort. With the imminent prospect of actually speaking to my father, I realised how completely unprepared I was for this to happen.

Together, Louis and I ran through all the how-will-you-feel-if's that we could conjure. I prepared myself for every form of rejection, disappointment, disillusionment, insult and seduction I could imagine. Finally, I hit on the weirdest possibility of all.

'He lives with another man!' I said.

'No,' said Louis, getting my drift.

'You never know. Two men in their seventies playing house. In Pasadena.'

'You're crazy.'

Still, the more I thought of it, the more sense this theory began to make. Details started to tie together: my father's handwriting, my mother's innuendoes, his sudden departure, his macho cover-up. Could it be that my father had left because he had no other choice, and how would that change my view of what he'd done? I fantasised about our reunion, pictured us introducing our mates, summer trips to Ischia, marches arm in arm with ACT UP.

Gently, Louis tried bursting my bubble. 'A lot of older men live together for companionship,' he said.

'Not my dad,' I answered, the word sounding strange in my mouth. 'Should I call him Dad? Or Pop? Or Father?'

'Just call him!'

Louis made me promise to phone Pasadena Jim the next morning, no matter what. That night I could hardly sleep. Every time I got up to pee, I saw the number staring at me in the dark, like a miracle, right in my face.

In the past 20 years, I have interviewed rock stars, movie stars, millionaires, Nobel Prize winners, rapists and people on their deathbeds. I have prided myself on nerves of steel when it came to extemporaneous chat, but that morning, dialling Jim Matousek's number, I was - for all practical purposes - four years old again.

He wasn't home. I thought I recognised the voice on the machine and hung up without leaving a message. I tried again, then again, then again, chickening out each time. Finally, I left a polite message asking him to call me back, collect.

He didn't. As the days passed, I convinced myself that he'd fled the country at the sound of my voice, too mortified to confront me.

On 8 August, I left one final, detailed message, telling Pasadena Jim exactly who I was and why I was calling. 'If you don't want to talk to me,' I said, unable to hide the hurt in my voice, 'then have someone else call me back and say so, immediately. Please.'

He called the next afternoon. When I heard his name, I held my breath. 'Dad?' I said. 'Is that you?'

'Mark?'

'Yes?'

'I'm not your dad.'

I looked out the window at the mountains. For a moment, I couldn't speak.

'You've got to be,' I said finally.

'I'm not.'

'But I have proof.'

He chuckled. 'Oh really?'

'Really.

'I don't think so,' he said, then told me that he'd never been married or had any children. He told me he wished he could help me. I opened my mouth but no words came out. Louis was sitting on the floor, shaking his head, looking dubious. Finally, I apologised for bothering him.

'No bother at all,' he assured me. 'Understandable mistake.'

'By the way,' I asked, 'what colour are your eyes?'

'Hell if I know,' the old man said. 'Blue, I think.'

'Not grey?'

'I'm colour-blind, son,' he told me.

'So am I,' I say.

'Isn't that a coincidence?'

'Isn't it?' I answered. Then I hung up the phone with a lump in my throat, unsure of what had just happened.

It was worse for Belle, when I told her. She doesn't have the consolation of knowing, as I do, that our father wanted her with him. My aunt Ruth said it was better this way. My mother snapped back to her coldness, saying she always knew he was dead.

Finally, I called Mack Sullivan, who simply couldn't believe it. 'Impossible,' he repeated several times. 'I was so sure. The chances. The odds. Something just doesn't add up here.'

'Sorry, Mack. He's not my father.'

'Well, I'll be damned_' Sullivan's voice trailed off. Then he offered to keep trying even though his sources had dried up. I told him not to bother.

Mystery is an acquired taste. When you've been weaned on uncertainty, grown up in a forest of question marks, improvised your very self from scraps and lies and innuendo, you acclimatise to unfinished business and the notion of life as a defective puzzle. After my last talk with the detective, two years passed in a hectic blur: I finished my book, my mother succumbed to lung cancer, and my own prognosis improved drastically with the advent of effective treatments. Then one stormy day in 1997, while visiting my family in California, I found myself in a rented car on the highway to Pasadena, looking for the address that Mack Sullivan had sent with a note in case I ever changed my mind.

The rain was lashing the windshield as I followed the road map, past the cemetery where we'd buried my mother. Had it been necessary for her to die, I wondered, before I could make this final journey? Or, rather, was it because she was gone that I now felt the urge for my father again? I can't say for certain but as I struggled to find his street through the deluge, I felt as if something important were coming, and was far more nervous than I had expected. After several wrong turns, I finally located the address and stopped in front of a modest stucco duplex set back behind a fenced-in garden. I pulled over to the curb and turned off the engine. The steering wheel was damp from the sweat of my palms.

I saw no sign of anyone home, no porch light or car in the driveway, but I'd promised myself to wait around for as long as this took. I smoked two cigarettes in a row, practised smiling in the mirror, chewed a very strong breathmint, then I opened the car door and walked quickly through the rain to the porch. The draperies were closed with no light on inside. The neighbour's dog started yapping madly. I held my breath and pushed the bell.

No response. I rang again. A minute passed and still no answer. I opened the screen and knocked on the door, first gently, then with a rap, but the house appeared to be empty. I crossed the porch and pushed the neighbour's bell, sending the dog into a frenzy, then heard someone mutter behind the door. A magnified eye appeared at the peephole. When I waved, the hole snapped shut.

I sat on Pasadena Jim's porch and waited. Five minutes passed. Fifteen. Twenty. Before I retreated to the car, I pushed the doorbell one last time. The door cracked open right away. 'Can I help you?' a man asked, his face invisible behind the screen.

'Mr Matousek?' I said.

'You'll have to speak up, son. My hearing aid is in the shop.'

'Are you Jim Matousek?' I asked louder, still unable to make out the face.

'I sure am. Can I help you?'

I hesitated before I answered. The rain was blowing in sideways torrents, splashing the porch steps, drenching my boots. For a second I wanted to run away, as my father had done that night in his truck, just turn around and disappear and leave him waiting without an answer. I thought of revenge, but just for a moment, then I got a glimpse of his eyes in the porch light he flipped on to see me better. They seemed to be grey. His face was unshaven. He looked at me with enormous kindness.

'Can I help you?' he asked again.

• The Boy He Left Behind: A Man's Search for His Lost Father by Mark Matousek has just been published by Piatkus.