Atypical sexual behavior is intriguing to many people, yet the empirical research on paraphilia and fetishism is relatively lacking. Nonetheless, clinicians are often called on to intervene in such cases, particularly when the paraphilia involves nonconsenting partners. This review article is structured around a brief historical overview of the diagnostic classification of atypical sexual behavior in the United States, descriptions of the types of atypical sexual behavior that receive clinical attention, an overview of the models that have been proposed to explain the development of atypical sexual behavior, and finally a summary of the most common treatments for these problems.