The nature of critical realist philosophy and its relevance to geography are outlined, including its fallibilism and distinctive way of understanding causation, which is especially appropriate for the study of the irregular behaviors that typically confront geographers. It also acknowledges that the intrinsically meaningful character of social phenomena requires interpretive understanding of meaning in society. Further, it defends a critical stance toward the ideas and practices studied by social researchers. Some implications for methodology are sketched, and illustrations are given of research informed by critical realism in geography. Finally, critical responses to critical realism are summarized