For tree identification 101 Trees of Indiana by Marion T. Jackson is the book that can't be beat.
It must have been the author's love for Indiana that made him put the Indiana in the title because the book would be a great reference for the entire eastern United States.
The book is the easiest and most comprehensive reference on trees that I have come across. Each tree is referenced by not only a photograph of leaves and bark but a photograph of twig, flower, and fruit is included. A map of Indiana references the counties where each tree can be found.
Additional references for habitat, wood uses, and wildlife importance as well as any underlying pests or diseases that affect each tree are included to make this one of the most complete tree guides that exist.
So whether you are interested in trees of Indiana or the whole eastern United States, 101 Trees of Indiana is a comprehensive guide for your shelf.