We have chosen The Story of the World: History for the Classical Child by Susan Wise Bauer for our primary resource for learning history.  At first I was a bit afraid our son will have trouble relating to the classical world but I was quickly proven wrong.  History has become one of his favorite subjects and to a great extent this book is responsible. We also use the The Story of the World: Activity Book to point us to other resources and activities.  This book recommends further reading of specific pages in several of popular encyclopedias for kids.  We use Useborne Internet Linked Encyclopedia of World History. Along with history our son learns geography of the areas of the world about which he is learning.  I print out maps from Blackline Maps of World History.