The second-hand bookshop in Edgware where I used to spend my weekends was just around the corner from the salt-beef bar. I rarely came home with beef-on-rye-no-mustard-one-fish-ball-please but I did buy dozens of mystery novels, Hardy Boys and the like, full of zipping conspiracies and handsome all-American teen detectives.

As a child, I couldn't get enough of this cheap, almost inexhaustible supply of second-hand books. Nothing, it seems, has changed. All the way through university, where I read Latin and Greek, I bought second-hand books (a little more expensive now): the epic poets Homer and Virgil in the original and in translation, learned commentaries, books about these books. The great thing about Classics is that - unlike any scientific discipline, say - things change relatively slowly. They do change, but what was written about the erotic poet Ovid 150 years ago is probably still of use today.

So, after four years, I had acquired a few hundred of these books, and it occurred to me at some point in 2007 to look through them and see who had owned them before me. I took off of my shelves every second-hand Classics book I had, sat amid the teetering piles of them and sorted those whose owner could be identified from those whose couldn't. Some had written their names and university, college or school inside, others had been more elusive and just put initials, which entailed some assiduous googling. Once I had these 40 or so, I decided to track down these owners and tell their stories. That's how Second-Hand Stories was born.

My theory was simple: everyone's life has a story worth telling, whether on the grand international stage or a private, intimate level. The eleven lives I pursued for Second-Hand Stories bore this out, from the man who led the resistance against the Nazis in Crete in the Second World War and a poet-priest who had a chaste love affair with a woman who wasn't his wife, to a young actor trying to crack Hollywood and two Latin teachers.

And, to make it all hang together, I started each chapter with memoir from my own life that in some way rhymes with what follows.

I decided to track down the owners of these books and tell their stories

Without exaggeration, I can say these lives covered the century and the globe. They go from an English child to an Australian retiree, via Oxford students, a Belgian exile, a visitor to fascist Italy, a rower who steered a boat from Greece to Soviet Georgia, a traveller through Afghanistan and a teacher in Papua New Guinea. They were witness to atrocities and triumphs, murders and miracles.

One of the most interesting lives was that of Peter Levi, the poet-priest and Afghan traveller. The way I found Peter is curious. I had bought a translation of the poems of Pindar, a Greek poet who wrote songs in praise of winners at athletic contests (not just the Olympian games but more); Pindar was paid by the winners, so the poems are masterpieces of sucking up. Inside the book was an inscription: "To Peter, with love and gratitude from Maurice." It was obvious that "Maurice" was Sir Maurice Bowra, an acid-tongued scholar and the translator of the poems. But who was Peter?

Having lunch with one of my old tutors, he suggested it could be Peter Levi. We looked in the introduction and there it was: the proof. "I owe a great debt to Father Peter Levi, S.J.," Bowra wrote, "who has read my text with generous care and made many wise suggestions." With such insight and luck did Second-Hand Stories develop.

Peter came from both Jewish and Catholic stock, but had an encounter with God while walking in a wood and realised he had to become a Jesuit priest. (His sister, now a nun, told me how a friend of his father's asked a young Peter what he wanted to be when he grew up, and when he replied "a missionary", put away the pound note he was about to give him and substituted a shilling.)

Peter, who established a glowing career as a poet of nature and spirituality, was always suspected by the church hierarchy, partly perhaps because they thought he might have divided loyalties, partly because of his own inability (or lack of desire) to follow the rules of which religious orders are composed.

He knew that faith was the real thing, although he constantly struggled with his own. Even so, when he met and gradually fell in love with the wife of a famous literary critic, it took the death of her husband and a decade before he decided to leave the priesthood.

All of the incredible second-hand stories came from a simple idea and, unlike a novelist, I didn't have to make anything up: it was all there in the variety, complexity and drama that their lives had, that ours all have. The next time you look at your bookshelves, just consider how your life is now part of their stories.

You can support Second-Hand Stories at www.unbound.co.uk