The queen of veganism herself, Kathy Freston's book Veganist ($15) discusses everything from weight loss to helping the environment and making your life more spiritual, all in respect to going vegan.
This book is filled with health success stories from people who changed their diet to a plant-based one and includes sample menus of Kathy's own meals so you can get an idea of the wide variety of food items vegans can eat.
Kathy recognizes that going vegan is a big commitment and suggests easing into it, so that it gets easier over time. An excellent "beginner's manual" for anyone who is ready to go for it!
Keep in mind that this book doesn't include any recipes.