Yes, Karen is right. Step Up Books are WONDERFUL for this stage of reading. The history books have titles such as
Meet Abraham Lincoln
Meet George Washington
Meet Andrew Jackson (and other “Meet…”
The Adventures of Lewis and Clark
My son loves the science series. Look for:
Animals (Insects, Fish, Reptiles…does contain evolultion) Do the Strangest Things
They also have Football Players Do Amazing Things and Magicians Do Amazing Things
They are all OOP but are worth seeking out. I have several duplicates because I pick them up whenever I find them.
These are older as well and OOP, but boys in my library really enjoy the Dan Frontier, Cowboy Sam and Jim Forest series. They are all graded readers with the beginning ones probably much too easy for your son, but they do get more difficult and are exciting.
Another (OOP…sorry…that’s what I do) wonderful series is Here Come the…series. Titles include:
Here Come the Bees, Here Come the Bears, Here Come the Deer, etc. They are all written by Alice E. Goudey, a wonderful science writer for children. The print is large with interesting narrative text. They are always checked out in my library.
Some of Robert McClung science books would be good for this age as well. I have Sphinx: The Story of a Caterpillar in front of me and it would be perfect. Avoid “The Last of…” books by him for reading at this level. More difficult than some of the others.
(Oh…and my 8yo read five Nate the Great books yesterday. He loves them.) 