At the moment, everyone's arguing about “what makes a children's book”. I think a children's book is one you'd most love to come across for the first time before you're fourteen. Simple as that. So make sure that you haven't missed a single one of these before your fourteenth birthday. And if you're a good reader, have a go at them sooner.

I'm assuming you've read Joan Aiken's Black Hearts in Battersea and The Wolves of Willoughby Chase already, but if you haven't, this is about your last chance. And that's true for Russell Hoban's The Mouse and His Child.

Have a few old-fashioned flashbacks. These are "the classics", coming up. First, you could read everything by Frances Hodgson Burnett. Start with The Secret Garden if you haven't read it already. Little Lord Fauntleroy is my favourite. And A Little Princess is really good. (Unusually, so is the film.)

E Nesbit is the writer I most wish I hadn't missed in childhood. (I don't know quite HOW I missed her, but I did.) The Railway Children is obviously the most famous. But do have a go at the others: Five Children and It. The Phoenix and the Carpet. The Treasure Seekers.

It would be shame to miss The Borrowers by Mary Norton. (The film's a pleasure, too.)

My favourite children's writer: T H White. He wrote The Once and Future King, which is the story of Arthur, and Mistress Masham's Repose. Both these books are back in paperback after years of shameful neglect, but during those years I found plenty of copies in second hand bookshops, and if you see any of them, buy them at once. I promise you won't be sorry.

If you haven't read The Silver Sword, by Ian Serraillier, then you've missed one of the finest children's books of the 20th century. It's such a classic there are plenty of copies around.

I doubt if you'll be lucky enough to find a copy of The Hunted, by Peter Carter. But I think it's one of the finest novels about wartime that I've ever read. (If you find one, I'll buy it off you if you don't want to keep it.) I feel the same way about Maurice Gee's The Fat Man. A brilliant book, but one that wasn't even published in Britain, even though it won prize after prize in Australia. If you see a copy of that, I'll take that, too.

If you haven't read Susan Price, you're in for a treat. But you won't find her second hand much yet. Try Head and Tails. Same with Hilary MacKay She has a series of comedies called The Exiles, The Exiles at Home, etc. But I doubt if anyone's giving them away yet.

But you will find Madeleine L'Engle books, and they are certainly worth taking home. Start with A Swiftly Tilting Planet, A Wrinkle in Time, etc.

And don't miss the Susan Cooper books that you'll find everywhere. Over Sea, Under Stone, The Dark is Rising. and more.

Margaret Mahy is always worth a read. Any title. And so is Jan Mark, if you can find her books. William Mayne and Peter Dickinson have tremendous fan clubs and people who just don't get them. You could stand there and have a bit of a read to see which camp you fall in.

You should have read Louise Fitzhugh's Harriet the Spy ages ago. But if you missed it, still just time to enjoy it a lot. Am I allowed to mention myself? The book that gets stolen most often during visits to schools is my Crummy Mummy and Me, but anything you see of mine you should pick up at once. Someone you know will want it.

Some books just never seem to be in second hand shops. Probably no point looking for The Great Elephant Chase by Gillian Cross. Or Aquila, by Andrew Norris. Or Harry and the Wrinklies, by Alan Temperley. Or anything by Geraldine McCaughrean. But you may well find J R R Tolkien's The Hobbit, or The Lord of the Rings. Don't miss them, even if you've seen the film.

I hardly ever see a Terry Pratchett novel second hand. But, when I do, I buy it.

You will find Jill Paton Walsh, and Nina Bawden and Robert Westall. And they're all writers not to miss.

I haven't finished, you know. I will be back. But this is more than enough to keep you going. And if you've already read them all, you certainly don't need me. You're doing fine already.