Among the diversity of perspectives for studying the nexus of evolution and human behavior, human behavioral ecology (HBE) emerged as the study of the adaptive nature of behavior as a function of socioecological context. This volume explores the history and diversification of HBE, a field which has grown considerably in the decades since its emergence in the 1970s. At its core, the principles of HBE have remained a clear and cogent way to derive predictions about the adaptive function of behavior, even as the questions and methods of the discipline have evolved to be more interdisciplinary and more synergistic with other fields in the evolutionary social sciences. This introductory chapter covers core concepts, including methodological individualism, conditional strategies, and optimization. The chapter then provides an overview of the state of the field, including a summary of current research topics, areas, and methods. The chapter concludes by emphasizing the integral role that human behavioral ecology continues to play in deepening scholarly understandings of human behavior.