Book excerpt: Robert K. Merton (RKM's) sociological work spans several decades: 1920s (i.e., childhood), 1930s (anomie, science, unanticipated), 1940s (housing studies, mass communications, structural-functional analysis, professions, focus groups), 1950s (reference groups), 1960s (ambivalence), and later-decades (structural analysis, sociological semantics, cultural sociology). He particularly contributed to sociology during a period when several specialties were being set-up and yet his work spans both general and specialist sociologies. He is recognised as the father of anomie/strain theory; focus groups; sociology of science; role-set theory; analytical sociology; structural-functional analysis; ambivalence studies; and sociological semantics, but always endeavoured to keep the multifarious threads of sociology together. RKM stood at the junction of many other crossroads: classical and modern sociology; US and European sociology; theory and research; philosophy of social science and applied sociology; pure academic sociology and applied sociology; cognitive and social; social sciences and humanities; social sciences and science. Yet the different components of RKM's work relate to each other. RKM had a major effect on the baby boomer generation of sociology who joined the ranks of sociology at a time of great expansion of university positions across many developed countries. Other generations since have been less exposed to his work.