Have you ever finished a business book and thought, "It should have been an article." It could have been 25 pages instead of 250 pages of fillers and fluff. This past week I read a book that's the opposite. It's called Write Useful Books by Rob Fitzpatrick. The book's premise is simple: the world needs more nonfiction books as long as they are short and insanely useful. Fitzpatrick follows his advice with a quick 136-page book packed with tips to write, test, and publish a useful nonfiction book.