I've never read A Bridge to Terabithia by Katherine Paterson but Bridge to the Past, an article from The Burlington Free Press (which I read when I'm in northern Vermont), is just a marvelous account of how it came to be written. (There are spoilers, by the way.) It's all about how art comes from life, if I'm not reading things into it.
Any writers who have ever been influenced by their children will go to pieces over this thing. Oh, almost anyone will be affected.
I've read some criticisms of Terabithia because some adult readers found the ending too difficult. I have to wonder if they would rethink their response if they were aware of how the book came to be.
Thanks to a member of the child_lit listserv for the link.