In this article, Sonya Shafer of Simply Charlotte Mason discusses how Charlotte Mason combines nature study with living books in order to create a more complete education. She says Charlotte Mason did not feel one was complete without the other. For example, living science books enable a child to verify what they have directly observed in nature. They also allow a child to fill in the gaps since it's not possible to observe everything in nature. Finally, they provide inspiration of things the child can look for while out in nature.
She suggests choosing books that have good literary value and that will touch on your emotions and fire your imagination. She says to look for both broad-overview books as well as ones that dive into the details of one particular item.
Click the link above to view the entire post and to see some specific recommendations on books.