With almost 80,000 titles currently in print, the self-help and how-to book category is one of the largest nonfiction genres. Your book can join this list if you convey information or dispense advice with knowledge and authority in a well-written, comprehensible, and informal style. If you are not an expert in your subject, you can consider a coauthor or rely on research and professionals to give you credibility. Not only is there a vast market for self-help and how-to books, but writing one can be rewarding and fun as well.