Rags to riches to libraries ... Andrew Carnegie. Photograph: Bettmann/Corbis

Here Lies Arthur by Philip Reeve, awarded the 2008 Carnegie Medal this afternoon, is the latest to enter a very select band of books. The award was set up by a Scottish American philanthropist, Andrew Carnegie, who apparently found such raptures in the libraries of his youth that he resolved "if ever wealth came to me that it should be used to establish free libraries"; he managed, incidentally, a grand total of 2800. The Carnegie has been awarded by children's librarians for an "outstanding" children's book since 1936, and a moment's browsing through the list of past winners suggests that those humble librarians have been a remarkably prescient bunch. Some of the greatest works of children's literature are here, from Watership Down by Richard Adams to Northern Lights, the first of Philip Pullman's magisterial trilogy.

But the real marvel of the Carnegie Medal is that it keeps alive books that remain less well known, that might otherwise be entirely, if unjustifiably forgotten. On the list of past winners are several books that I tend to think of as my own private discoveries, books ferreted from grandparents' attics or pounced upon in market stalls. Though it's a little galling to discover that I am not the only person who thinks that 1941's winner, The Little Grey Men by BB (actually Denys Watkins-Pitchford, a one-time art master at Rugby school) is a terrifically moving elegy for an England now almost extinct, it is gladdening in the extreme to know that other people have also been beguiled by the beauty of a meticulously observed countryside inhabited by gnomes with a passion for pipe-smoking.

Another old favourite, A Stranger at Green Knowe, the fourth in a magical series of books by Lucy M Boston, took the prize in 1961. It is the landscape that has stayed with me through the years, part of that rich interior topography that is the inheritance of the youthful reader. The ancient, moated Green Knowe is one of literature's most evocatively drawn houses; as well as its chatelaine, the charming Mrs Oldknowe, it is tenanted by ghosts and, in this book, an escaped gorilla

Both books share a fierce love for the wild, the overlooked and the underdog, and their enchanted landscapes are not devoid of horrors. The gibbet in The Little Grey Men, hung about with the corpses of tiny birds, not only introduced me to a new word; it also provided me with an image of the kind of relentless, wasteful cruelty that, sixty years on, has laid waste to the countryside BB so loved. And the unsentimental empathy with which Lucy M Boston depicts her two refugees, one a Chinese orphan and one a gorilla snatched from the Congo, is intensely appealing to a child's innate sense of justice.

But it is aesthetic appeal that really makes a book linger in the mind through the decades. When I think of The Little White Horse by Elizabeth Goudge, 1946's winner, a flood of images is dislodged: the salmon-pink geraniums that are so central to the plot, Maria's grey and violet dresses, and her tiny, tower-top bedroom remain with me to this day. Like many children's books written during the war years, it is intensely preoccupied with sensual pleasures (indeed Evelyn Waugh, in his preface to the 1960 edition of Brideshead Revisited confessed to something similar: "It was a bleak period of present privation and threatening disaster - the period of soya beans and Basic English - and in consequence the book is infused with a kind of gluttony, for food and wine, for the splendours of the recent past, and for rhetorical and ornamental language").

In my rather battered copy, the list of dishes served at the fabulous tea-party that concludes the book is faintly underlined in pencil, a habit of my sister's during our own period of soya bean privation (caused not by war but an ill-fated maternal experiment with vegetarianism during the 1980s). Who could blame her? The litany of "plum cake, saffron cake, cherry cake, iced fairy cakes, éclairs, gingerbread, meringues, syllabub, almond fingers, rock cake, chocolate cakes, parkin, cream horns, Devonshire splits, Cornish pasty, jam sandwiches, lemon-curd sandwiches, lettuce sandwiches, cinnamon toast and honey toast" is enough to whet my appetite to this day. It's a feast for the imagination, which is just what a children's book should be. Though I should spend the summer ploughing through past Booker winners, I can't help but wonder what treasures the rest of the Carnegie list conceals.