Science
If you think science is difficult, these books are meant for you. They focus on the quest to understand the universe, from Thales to today's cosmology. Reading them you'll meet Pythagoras (a great mind, but a strange man), Archimedes (he could do everything), Isaac Newton (not very likeable), James Clerk Maxwell (a shy Scotsman who did the math that led to the electromagnetic revolution), and Einstein (who not only brought us relativity, but confirmed the atom and laid the foundation for quantum theory). Quantum theory? Relativity? What are they? Read these books and you'll find out.
The Story of Science by Joy Hakim
The Story of Science Aristotle Leads the Way The Story of Science Newton at the Center The Story of Science Einstein Adds A New Dimension
The Story of Science:
Aristotle Leads the Way
The Story of Science:
Newton at the Center
The Story of Science:

Einstein Adds a New Dimension

All three books in The Story of Science are published by Smithsonian Books in association with the National Science Teachers Association.
Smithsonian Books
NSTA