I'll Go On Barbican Pit, London ****

"My life - a joke that still goes on." So speaks Molloy in Samuel Beckett's novel, the first of the agonising post- war trilogy of being and nothingness that spans Mol loy, Malone and The Unnamable. These are works that read more like the longest suicide note in history than novels. Only there is no body. Out of the ashes of these books was born the consummate artist who wrote Godot, Happy Days and Krapp.

Beckett notoriously disliked seeing his work adapted from one medium to another, but it was wise of adaptors Gerry Dukes and Barry McGovern to ignore this. Their expert filleting of Beckett's "wordy gurdy" down to a manageable 75 minutes is a triumph. For as the lives of the protagonists dissolve so does the narrative, until all you have are voices. A very simple, pure kind of theatre. Even purer here, because one actor, the brilliant McGovern, plays the three voices, which are also just one voice - that of the author - and many voices, all the world's Molloys, Malones, Murphys, Merciers, and Morans, who conjoin in one jabbering scream of despair.

First there is Molloy in his hated mother's room, his life a slippery confusion of hilarious narratives about crashed bicycles and dead dogs and parrots. It becomes increasingly clear that this man's identity is as doubtful as his stories. There are no certainties here, only a dissolution. An inevitable melting into a state worse than amnesia, a sense of someone we sighted long ago and had forgotten. Perhaps a glimpse of ourselves as we pass the mirror.

Things get worse with Malone, a man who tells jaunty stories while he waits to die - already, in McGovern's desperate, astonishing performance, an effigy on his own tomb. This is the reduction of the world to eating and excreting while you wait for the final oblivion.

But there is no end. The Unnamable brings us someone, now utterly unidentifiable, in purgatory, forced in mounting panic to speak. A frenzy of words like a terrible storm that obliterates him entirely, words like bullets that cut him down. It is this voice, so insistent, so unstoppable that it follows you in the silence as you leave the theatre. All the way home. All night it whispers insistently in my ear: my life - a joke that still goes on and on and on.

Until July 29. Box office: 020-7638 8891.