"The Master Key System by Charles F. Haanel. I have read hundreds of personal development books, but this is the one that clearly showed me how to visualize, contemplate, and focus on what it was I truly wanted. It revealed to me that we only get what we desire most, and to apply myself with a laserlike focus upon a goal, task, or project. That in order to "have" you must "do," and in order to "do" you must "be"--and this process is immediate."