Although causal reasoning is a component of most human cognitive functions, it has been neglected in cognitive psychology for many decades. To date, textbooks on cognitive psychology do not contain chapters on causal reasoning. The goal of this Handbook is to fill this gap, and to offer state-of-the-art reviews of the field. This introduction to the Handbook provides a general review of different competing theoretical frameworks modeling causal reasoning and learning. It outlines the relationship between psychological theories and their precursors in normative disciplines, such as philosophy and machine learning. It reviews the wide scope of tasks and domains in which the important role of causal knowledge has been documented. In the final section it previews the chapters of the handbook.