In this article, which comprises the third chapter of Studies in Ethnomethodology, Harold Garfinkel analyzes everyday social procedure that he calls, following Karl Mannheim, “a documentary method of interpretation”. The method consists of treating an actual appearances of the events as “the document of”, “pointing to” or “standing on behalf of” a presupposed underlying pattern of these events. Not only is the underlying pattern derived from its individual documentary evidences, but the individual documentary evidences, in their turn, are interpreted on the basis of “what is known” about the underlying pattern. To illustrate the main idea, the article discusses an experiment that involved the creation of situation in which subjects sought for a meaning and pattern underlying the sequence of fully random utterances of the interlocutor. As Garfinkel shows, documentary method of interpretation is used both in everyday life and in professional sociological research for the production of the “facts” concerning social structures. Members of society, professional sociologists included, use and treat such descriptions of a society as known in common with other members, and with other members take them for granted.