Ethnomethodology and Conversation Analysis have made major inroads into the disciplines that make up the social sciences. Although commonly run together under the title of EMCA, what their relationship is to one another remains as elusive as the relationship between their respective founders, Harold Garfinkel and Harvey Sacks.This book clarifies the nature of these relationships, demonstrating that Harvey Sacks’ studies of the sequential organisation of conversation are the cardinal example of what Garfinkel described as an ethnomethodological alternate to traditional social science. However, over the decades that have passed since Garfinkel developed ethnomethodology, several confusions have arisen as to what he meant. The author argues that these have resulted in a blunting of Garfinkel’s original intentions which compromise the adequacy of ethnomethodological description. In response, this book shows how Sacks’ considerations of adequacy can ground ethnomethodology as a “natural observational science” that redirects it towards developing further coherent and precisely circumscribed bodies of work to those of Sacks’ own coherent and precisely circumscribed studies.It will appeal to both new and existing scholars of ethnomethodology and conversation analysis, as well as those with interests in social theory, methodology, and those who have taken up the relevance of conversation analysis for their research and are interested in the ethnomethodological heritage of conversation analysis.