Book Of A Lifetime: The Diary of Samuel Pepys

One's book of a lifetime should become a total obsession – a work that leaves you seeing the world through different eyes. For me, it's the unexpurgated 'Diary of Samuel Pepys'. Completing the 11-volume set challenges even the most dedicated, but the entries are so vivid and comprehensive that the readers feel almost as if we're living a parallel life.

Written between 1660 and1669, the daily diary seems to have become an essential ritual for Pepys. Nothing escapes notice - whether a meeting with the king, the goings-on at the Navy Office, kissing a pretty girl, or the number of farts Pepys passes. Through it all we track Pepys's astronomical rise from impoverished young hopeful to the most influential mandarin in the Navy bureaucracy.

Covering the Restoration, the Great Plague, the Great Fire of London, and the invasion of the Dutch, the 'Diary' encompasses arguably the most turbulent period in London's history. And the worse things get, the better Pepys' sex life becomes. His philanderings are legendary, but it's the rich and complex relationship with his wife Elizabeth that often makes the entries unputdownable.

Pepys is no bit player in the great events of the day. He helps bring Charles II back to England, follows bodies to the plague pits with morbid fascination, and frantically buries his Parmesan cheese in the garden as the Great Fire approaches. In later life he became president of the Royal Society, and some of its more extraordinary early experiments are documented in the diary's pages.

And what a London acts as backdrop to all this! Public toilets do not exist and the water's undrinkable, so for the young Pepys it's beer for breakfast and lunch, and wine – if he can afford it – for dinner. In the Navy office, the management of accounts is almost as sozzled as young Pepys. Somehow he finds himself giving up the rowdy lunches with his fellow clerks and coming to grips with the Augean stables that is Navy business. By the diary's end, under Pepys's guidance, we can see the infant glimmerings of a modern Navy taking shape.

For all the unfamiliarity of Restoration England, there is something very modern about aspects of Pepys's life. Anyone familiar with 'Yes, Minister' will recognise many of his work-life dilemmas, while any spouse will sympathise with the agonies – and perhaps secret triumph – of Elizabeth when she catches Pepys in flagranto delecti with the maid. Certainly, their make-up sex would not be out of place in a racy television drama.

Even though so much has changed, on visits to London now I see the city in part through Pepys's eyes. And there's one place of pilgrimage I invariably visit: St Olaf's church, where Pepys and Elizabeth were buried. It's also the place where the great diarist gazed unabashedly upon the local beauties, while he mastered the art of masturbation without using his hands. In the end he got so good at it that he could even climax without blinking.

Tim Flannery's 'Here on Earth' is published by Allen Lane