Donald Davidson has prepared a new edition of his classic 1980 collection of Essays on Actions and Events, including two additional essays. In this seminal investigation of the nature of human action, Davidson argues for an ontology which includes events along with persons and other objects. Certain events are identified and explained as actions when they are viewed as caused and rationalized by reasons; these same events, when described in physical, biological, or physiological terms, may be explained by appeal to natural laws. The mental and the physical thus constitute irreducibly discrete ways of explaining and understanding events and their causal relations. Among the topics discussed are: freedom to act; weakness of the will; the logical form of talk about actions, intentions, and causality; the logic of practical reasoning; Hume's theory of the indirect passions; and the nature and limits of decision theory. The introduction, cross-references, and appendices emphasize the relations between the essays and explain how Davidson's views have developed.