OK, here's a theory that every book lover will want to put to an immediate test.

In the Guardian last week, blogger Charlotte Stretch wrote about Marshall McLuhan's notion that to determine whether or not you will like a book, turn to page 69. If what you read there strikes your fancy, you will probably enjoy it. If not, you shouldn't bother.

(This is akin to a theory held by some musicians. They insist that you can discover the worth of an album – dated term I know but nonetheless – by listening to track 7. That, they say, will give you your answer.)

Anyway I immediately put McLuhan to the test with three of the books we reviewed in the Monitor this week. The results were mixed at best. On pages 69 of both "The Last Island" and "Broccoli and Other Tales of Food and Love" there was very little text. And what I read of "Broccoli" (a book I quite enjoyed) on that page signally failed to grab me.

Of course it's also true that these books are, respectively, a volume of poetry and a short story collection – perhaps not the kind of books that McLuhan had in mind. So I tried again with "For the Love of Animals" and found that, yes, page 69 grabbed me and would have decided me in favor of the book.

However, I'm not a convert. At least for now I'm sticking with my own more labor-intensive theory. If a book looks good to me, I give it 50 pages. (This, of course, applies to pleasure reading – not reviews. On those I have no choice!)

If I'm not hooked by page 51, I quit. I may have missed some good ones this way, but on the balance, I suspect my system has served me well.