In that Meg Ryan/Tom Hanks movie You've Got Mail, the Meg Ryan character owns a children's bookstore. "The things you read as a child," she says, "become part of who you are the way no other reading in your life ever does." (Or something like that, anyway.)
This is one of my favourite books from my childhood; Rosemary Sutcliff's Eagle of the Ninth. I loved everything she wrote, but I only owned a few of her books, and this one is worn out pretty well. It's an old Penguin edition, from 1983 or thereabouts. The pages are yellowed, the font is uncomfortable to read, it's unpleasantly flimsy in my hands and feels like the spine may crack at any moment. Speaking of the spine, it's faded several shades lighter than the covers, because it's lived on many bookshelves since it came into my possession. (Now that I think about it, it's possible this isn't the copy I owned as a kid, but rather one that I picked up along the way, at a garage sale or something. Most of my childhood books vanished after I left home.)
A librarian of my acquaintance told me that one of her challenges is re-ordering books that the library already owns, because after the covers stop looking current the kids don't borrow the books any more. Who, after all, would pick up a book with a cover like that 1983 Penguin when they could have this:
a re-issue of Sutcliff's Frontier Wolf, which I bought the other day?
I'm halfway through this book, and I have to say that I am loving it every bit as much as I did when I was a kid. (It was originally published in 1980, and Sutcliff died in 1992.) She wrote historical fiction that was primarily about Roman Britain, which is a period I still find very interesting. It's just so compelling: the legions arriving in Britain, the rebellion led by Boudicca, the settlement of most of the island, the building of Hadrian's Wall, the fall of Rome and what happened to the place after the legions left. The fact is that we don't know much about the period at all, but coming as I do from a place where a hundred years is a long time, the idea of remnants from almost 2000 years ago is enough to capture the imagination and never let it go. Some of the first (cough DREADFUL cough) fiction I ever wrote was in blatant imitation of Sutcliff's style and themes. Going back and re-reading these books has been a real treat: they are still as fresh, still as interesting, and still as absorbing as they ever were.
So the moral of the story, as it were, is that maybe you can't judge a book by its cover, but changing that cover can certainly make you pick up and rediscover the book.