When Bugs Were Big, Plants Were Strange, and Tetrapods Stalked the Earth
Hannah Bonner 2003 National Geographic
This illustrated kid's book deals with the Carboniferous and Permian periods and covers climate, plate tectonics, and paleontology. The cartoons are wonderful and often involve plays on words. The science is quite good and the book includes brief sequences on scientific disputes about the behavior and physiology of extinct organisms. There is a wonderful linear-scale geologic timeline in the back. It also includes an index and a list of web resources.