This book is a concise intellectual biography of Harold Garfinkel, a key figure in 20th-century social science. Garfinkel is practically synonymous with ethnomethodology, an approach that since the 1960s has led to major analytic and methodological developments in sociology and other disciplines. This introduction to Garfinkel explores how he developed ethnomethodology under the influence of Talcott Parsons and Alfred Schutz, situates it within sociology generally, and demonstrates its important influence on recent developments in the discipline, particularly the sociology of science and technology, gender studies, organization studies, and the computer sciences. The book will be of wide interest in the social sciences and a useful supplement to courses on intellectual history and methodology.