This chapter will explore the concept of sexual addiction, but let us start with what sexual addiction is not. It is not about a high sex drive or about liking a lot of sex. It is not about the kind of sex that you like or what you want to do alone or with another person. Nor is it about your sexual fantasy life or what you think about or look at when you masturbate. Sex is a normal human need and a persistent human longing; that is why we call it a ‘drive’ instead of merely an option. In the human species, there is considerable variation across a wide spectrum of possible sexual alternatives, from straightforward heterosexual vaginal intercourse, and all the possible variations involved in that, to same-sex behaviour with all of its possible variations. Sexual addiction is not about same-sex behaviours or a preference for solitary behaviours. Nor is it about preferences for group sex, bondage, dominance and submission, or anything else some might describe as unusual. This book is not about not having sex. It is about having good sex that you can enjoy and feel good about after you have done it.