The first book I bought on native plants was 100 Easy to Grow Native Plants: For Canadian Gardens. It is written by Lorraine Johnson who lectures on native plant ecosystems at York University and is the author of numerous books on gardening and environmental issues. She is well known for her bright sneakers (usually red) and funky earrings.
It was the perfect book for me, at the time a novice native plant enthusiast. The size is on the small side, with full colour photos on every page, and loads of practical information. It is divided in areas such as prairie, woodland and wet soil types, as well as, northeast, central and western. But of course since no plant exists on its own many cross over from one type of habitat to another. If, for example, you decide to check out Adiantum pedatum the maidenhair fern which is primarily an eastern fern, she will direct you to the western maidenhair fern (A. aleuticum) in case you live in the west. There are also multiple suggestions for good companion plants.
It is not a preachy book, just straight forward. The plants are easy to grow and easy to find at the nursery too. I have owned this book for more than 10 years and I still pull it out now and again for reference and ideas. So if you want to try your luck at growing native plants this is a great book with which to get started.