A book about children’s books is, of course, one for the grown-ups, but it is a subject that holds us long after we’ve joined the readers-aloud rather than the read-to classes. CS Lewis, who was perceptive about the allure of children’s books (he would be, wouldn’t he), observed that he read children’s books with pleasure as an adult in the same way that as an adult he still enjoyed lemon squash; the difference was that he now also enjoyed port. The point is, grown-up literary pleasures do not cancel out childish ones (at least, not the good sort); they just add to them.