This chapter is about what happens to the brain when someone becomes addicted to gambling. It aims to help you understand better what you are up against when you try to break free from gambling. Because we are reviewing relevant research and theories, this book reads more technically than other chapters in the book. We are hoping that reading it will help you appreciate that you are up against a tricky brain. The skills covered in the rest of the chapters of this book are meant to help you re-train your brain. Applying the stimulus control, mentioned in the previous chapter, will help you ‘buy’ the time you need to re-train a tricky brain, taken over by gambling.