The Chronicles of Narnia by C.S. Lewis

C. S. Lewis was famous both as a fiction writer and as a Christian thinker, and scholars sometimes divide his personality in two. Yet a large part of Lewis's appeal, for both his audiences, lay in his ability to fuse imagination with instruction. "Let the pictures tell you their own moral," he once advised writers of children's stories. "But if they don't show you any moral, don't put one in."