A striking characteristic of addictive behavior is the pursuit of immediate reward at the risk of longer-term detrimental outcomes. It is typically accompanied by the expression of a strong desire to cease from or at least control consumption that has such consequences, followed by lapse, further resolution, relapse, and so on. Understood in this way, addiction includes substance abuse as well as behavioral compulsions like excessive gambling or even uncontrollable shopping. Behavioral economics and neurophysiology provide well-worn paths to understanding this behavior and this book regards them as central components of this quest. However, the specific question it seeks to answer is, What part does – the desires we pursue and the beliefs we have about how to accomplish them – play in explaining addictive behavior?