Peter Michael Blau was an American sociologist and theorist. Born in Vienna, Austria, he immigrated to the United States in 1939. He completed his PhD doctoral thesis with Robert K. Merton at Columbia University in 1952, laying an early theory for the dynamics of bureaucracy. The next year, he was offered a professorship at the University of Chicago, where he taught from 1953 to 1970. He also taught as Pitt Professor at Cambridge University in Great Britain, as a senior fellow at King's College, and as a Distinguished Honorary professor at Tianjin Academy of Social Sciences which he helped to establish. In 1970 he returned to Columbia University, where he was awarded the lifetime position of Professor Emeritus. From 1988 to 2000 he taught as the Robert Broughton Distinguished Research Professor at University of North Carolina, Chapel Hill in the same department as his wife, Judith Blau, while continuing to commute to New York to meet with graduate students and colleagues.

Sociology is the scientific and systematic study of human society that focuses on society, human social behavior, patterns of social relationships, social interaction, and aspects of culture associated with everyday life. Regarded as a part of both the social sciences and humanities, sociology uses various methods of empirical investigation and critical analysis to develop a body of knowledge about social order and social change. Sociological subject matter ranges from micro-level analyses of individual interaction and agency to macro-level analyses of social systems and social structure. Applied sociological research may be applied directly to social policy and welfare, whereas theoretical approaches may focus on the understanding of social processes and phenomenological method.