I'm quite fond of Eric Maisel's books. He's a psychotherapist and "creativity consultant," and he has written a number of books on writing, art, and creativity. Several of them are among my favorite writing books: "Living the Writer's Life," "Deep Writing," and "Write Mind." Unlike those books, "The Creativity Book" is not aimed specifically at writers. It's aimed at you, me, your brother, and the guy in the cubicle down the hall. In other words, anyone who'd like to use a little more creativity in their lives, whether for painting, writing, mathematics, relationships, or business plans.
The book is designed to be read one section at a time, to take you through a year of learning. It has 88 sections, two per week, to get you through ten months, and then the idea is that you spend the last two months of your year devoted to a particular creative project. Each base section is pretty short--generally a page or three--so you'll have no trouble reading it in a few spare minutes some evening. Then it's followed by at least one exercise, and sometimes several. Sometimes the exercises are very specific; at other times, Maisel suggests ways to apply the exercises to whatever area you're trying to become more creative in.
Many of the ideas in the book are relatively basic, but this in no way makes them useless. After all, they're only basic for people who are already highly creative and making abundant use of that creativity. In large part this book is designed to help those who aren't sure where to start when it comes to creativity, and who haven't had much luck sitting down and getting started with their creative projects. Even highly creative people will still find things of value in this book, however. Some sections will feel like remedial schooling, but others might unlock surprising ways for you to move forward in your work. People with more experience using their creativity might prefer to skip from section to section instead of following the "plan," however, using the bits that have particular value to them.