This chapter provides an introduction to the Handbook, setting the scene for the subsequent chapters by covering several key topics in psychological research on alcohol consumption, such as why do people drink alcohol, how drinking patterns are defined (e.g., heavy episodic drinking, low-risk drinking), and how do governments and health agencies encourage performance of low-risk drinking. The chapter goes on to discuss issues of definition and measurement of alcohol consumption in psychological research studies, beginning with a focus on limitations with self-report measures used in most studies, before a brief discussion of alternative (biological measures, observation) methods to measure consumption. The chapter ends by introducing the five sections that comprise the book.