This posthumously published blend of fact and fiction, an informative and unsettling portrait of a great man and his times, starts with the 75-year-old Einstein answering a call from a female student who dialled his number by mistake. Their conversations frame the book, the rest of which follows his life chronologically, illustrating it with photographs and letters.

What hold the syncopated narrative together are Einstein’s own words, quoted throughout. His ability to speak in aphorisms is evident at seven: “The more I learn, the more I realise how much I don’t know.” In his last year, his utterances range from the obvious – “All of us are together on this small Earth, yet each person thinks that he’s at the centre of it” – to the pithy: “Creativity is the residue of time wasted.”

A recurring theme is fear, which begins with Jew-baiting at school and never ends. It intensifies as the world descends into one war after another, making Einstein a lifelong pacifist. There is also a deeper, more troubling fear of madness, collective and individual alike. Being a great scientist comes at a high personal price, with anxiety constantly throbbing beneath. “His one sanctuary is work,” Gadney tells us – a one-sentence definition of a genius Einstein himself might have coined.

• Albert Einstein Speaking is published by Canongate. To order a copy go to guardianbookshop.com.