The goal of this book is to provide a comprehensive description of tic disorders, trichotillomania, and other repetitive behavior disorders, with an emphasis on behavioral assessment and treatment. The material in this book stems from our (DWW and RGM) research and clinical work with individuals experiencing these disorders. Although we have done substantial work in this area both together and with our respective graduate students, our work has been inspired by the earlier ground breaking work of Nathan Azrin. 
Nathan Azrin was a pioneer in the development of behavioral technology for the treatment of a wide variety of psychological and behavioral disorders. Azrin's work in the 1970s and 1980s resulted in a number of innovative approaches to treatment that are still the gold standard today. The treatment 
that has been the impetus for our work is the Habit Reversal procedure Azrin developed and evaluated in the early 1970s. Habit Reversal, described in detail in a number of chapters in this volume, has stood the test of time. A large body of research demonstrates its effectiveness for the treatment of tics, trichotillomania, and other repetitive behavior disorders. Because of its robustness, accessibility, and wide applicability. Habit Reversal is given prominence in this volume. Our hats are off to Nathan Azrin for making it all happen. 
We have organized this volume and structured the information in the respective chapters with the practitioner, researcher, and student in mind. Important characteristics of tic disorders, trichotillomania, and other repetitive behavior disorders are described so the nature of these disorders, their comorbid conditions, and probable controlling variables can be understood. Both ground breaking and recent research on the analysis and treatment of these disorders is presented. Finally, Habit Reversal treatment manuals are provided for each category of disorder as step-by-step guides for practitioners and researchers treating these disorders. The authors of each chapter are active researchers and practitioners who bring a wealth of expertise to their respective chapters.