Peter Blau was born in Vienna in 1918. He emigrated to the USA in 1939, and gained a Ph.D. at Columbia University in 1952. From 1953 to 1970 he taught at the University of Chicago before returning to Columbia, where he remained until 1988. From 1988 to 2000 he taught as an emeritus professor at the University of North Carolina, Chapel Hill. His sociological speciality concerned an investigation of organisational and social structures. Although he is usually noted for his contribution to grand theorising, and, in particular, to organisational theory, Blau also developed a ‘microstructural’ theory of exchange and social integration (Blau, 1960). This work on social (as opposed to economic) exchange, including flows of advice, esteem and reputation, and its interaction with group power structures, led to his landmark book Exchange and power in social life (1964). His thinking here became important in the later formalisation of exchange theory by Richard Emerson. Such an analysis, however, was not at variance with his macrosociological considerations, as he viewed individual-level outcomes such as competitiveness and cooperativeness as being at least somewhat derivable from ‘structural effects’. In this respect, his attraction to exchange theory lay partly in his belief that it could provide a means to forge a link between micro-and macrosociological perspectives. In 1974, he served as president of the American Sociological Association.