This is the introductory chapter of Behavior Management in Dentistry for Children. The book has two main purposes: (i) to introduce current information basic to the understanding of children's behavior; and (ii) to describe and discuss many of the techniques and methods, new and old, used for promoting the cooperative behavior of children. The concept of the pediatric dentistry treatment triangle has provided the framework for the book. This chapter presents the definition of behavior management in relation to dentistry for children. The importance of behavior management becomes more important when assessing the effects of dental anxiety. It completely limits, or partially limits, utilization of health care.