Although there is only one ergative language in Europe (Basque), perhaps one-quarter of the world's languages show ergative properties, and pose considerable difficulties for many current linguistic theories. R. M. W. Dixon here provides a full survey of the various types of ergativity, looking at the ways they interrelate, their semantic bases and their role in the organisation of discourse. Ergativity stems from R. M. W. Dixon's long-standing interest in the topic, and in particular from his seminal 1979 paper in Language. It includes a rich collection of data from a large number of the world's languages. Comprehensive, clear and insightful, it will be the standard point of reference for all those interested in the topic.