D'Aulaires' Book of Greek Myths - Ingri d'Aulaire, Edgar Parin d'Aulaire

Absolutely formative and a huge part of my childhood and the adult I grew up to be.  This was one of the number one books I purchased upon having my own kid.  I don't think a home library can be complete without this book.  Since then I've discovered many other delights written by the D'Aualaires (Trolls and Norse Myths).  For me, there is no better Greek Myth collection for children - even if the Kraken does look a little like a hamburger patty in drag....