For those businessfolk who fret about productivity, take a break and read a book

I was in my favourite charity book store the other day when a fellow customer took a call. Someone on the other end was wondering where he was, and why something hadn't been delivered yet.

The chap was wearing the uniform of a courier service. He held his phone crooked between his ear and his shoulder while he turned the pages of Alistair MacLean's The Golden Rendezvous, and seeing the cover made me happy because I read that when I was a kid and it was jolly exciting and full of derring-do on a ship at sea, and suddenly I could recall lying on my bed and the layout of my bedroom and the hot Durban night while I read past my bedtime with the smell of frangipani and guava and loam through the window and the mornings before school while I lingered over my Coco Pops, trying to get in a couple more pages while my mother shouted from the car. Should I read it again? Would it bring back that feeling of being young and breathless and alive to adventure?

"No, I'll be there now," said the courier to the telephone. "I'm just stuck in traffic."

He hung up the phone and carried on scanning the book until he was satisfied this was the one for him; then he bought it for R7 and walked briskly out to his van.

Now many readers of this page are no-nonsense business folk who fret about productivity and work ethics, but I am not, and so I tell you straight it delighted me to see a chap with his priorities right. Someone needs a package delivered? Sure thing, as soon as I find something good to read.

But it set me thinking about reading books, and the books I've read, and that was alarming because it gave me yet another horrifying way of measuring the passage of time and how quickly that passage passes. I happen to keep an informal record of all the books that I read: it's a habit I've had since 1999, when I started jotting them down in the back of my journal as I finished them, I suppose as a way of leaving breadcrumbs through the forest behind me.

By going back over my lists now - as I did this morning when I woke too early and all the rest of the world was sensibly asleep - I estimate that over the years I've read a conservative average of four books a month. That seems a reasonable amount, until you start to do the figures. At that rate, with some adjustments for school and university and break-ups and those years when I was attending rather too many parties, I would offer a rough guesstimate that, since the age of six, I have read around 1920 books. That's 1919 books, plus The Golden Rendezvous.

This is astonishing to me. This is literally almost unbelievable. If you'd asked me this morning, before I'd done the maths, I'd have sworn up and down that I've read 10000 or 20000 books or 30000 books. As far as I'm concerned, I'm made of books. All that I am is books, plus the occasional movie and cricket Test. What thoughts do I have, what responses to the world, what feelings of love and loss and longing that haven't found their form in me filtered through the things I've read? But only 1920 books? How can everything inside, this universe of enthusiasms and associations that we each contain, be woven with such slender thread? And there's been so much guff along the way, taking up time and shelf space in my mind - novels with recipes; J. Randy Taraborelli's biography of Madonna; the rubbish you sometimes read because the author is an acquaintance. How much richer might I be if only I'd realised sooner how short life is, and how few read books it contains.

In my house alone I have shelves containing 4,500 books. To read them all at this rate would take me to the age of 120. Generously estimating expiry at age 80 - a good 15 years older than my father was - I'm just about 1600 books from the end. This is chilling and also instructive: every book from now means another for which I won't have time; I must choose with more care and execute with more gusto. I hope that courier enjoyed The Golden Rendezvous. I hope he took time away from work to read it.