This chapter is the heart of the book; it presents comprehensive deterrence theory (CDT), the reconceptualization of classical deterrence theory. It identifies the core principle of CDT, additional principles that flow from consideration of the intrinsic elements, and predictions that can be made based on them. The chapter presents both a set of core theoretical arguments and a wide range of corollaries that predict when and how legal punishment deters. The theory argues that deterrence consists of all eight intrinsic elements that individually and collectively deter crime. An essential insight from CDT is that there is no universal deterrent effect of a given punishment. Rather, deterrence involves contingent effects that depend on the configuration of the intrinsic elements. Because these can vary greatly, so, too, can the effects of punishment. This insight has profound implications for understanding the limited state of research to date, limited generalizability of many extant studies, and ineffectiveness of many policies. It also has implications for understanding how policy could be improved.