I have the complete set of "The Young People's Encyclopedia of the United States". 3 books in total. They are brand New! I bought them for my son, he never even opened them up.
These are full of illistrations and is very easy to read.
They are full of:
History, LIterature and the arts, People and Culture, Geography, Science and Space, Government and the Law, Religion, philosophy and myth, Sports and Pastimes, Countries and Places, Animals, Plants and food, States and cities.
If you have any questions, just send me an email.