This chapter discusses the centrality of deterrence to criminological theory and to policy, and then highlights critical shortcomings in classical deterrence theory. It points to critical problems that these shortcomings create, including incomplete or inaccurate understanding of deterrence and ineffective policy. The chapter then describes the motivation for the book, which is to advance theory and policy, the structure of the book, each of the chapters, and recommendations for sequences of chapters readers can follow to pursue their particular interests.