Love You Forever by Robert Munsch
Illustrated by Sheila McGraw
Published by Firefly Books

With a down-to-earth message of love, a mother sings the same song to her child even as he grows older and older.  Finally he is a grown man and she has become an old woman.  When she can no longer rock him and sing to him, he does the same to her.  A beautiful reminder for every child that their parents will love them no matter how old they are, no matter what they do, and no matter where they go.  Love You Forever is the sort of book to bring parents and their kids together after each reading.