In order to explain this changing focus of attention by delinquency researchers, this article explores the interrelationships among four types of factors: social and political conditions, ideology, current sociological theory, and available methods. We focus on ideology and methodology, and argue that when ideology is largely centrist, such as during the 1950s and 1960s, theory would most likely be interactionist or subcultural and gangs would likely be of interest. During periods of greater ideological polarization, such as the late 1960s, however, we would expect to find more theoretical and empirical concern with either the individual or with social and economic structure and little interest in gangs. (Publisher abstract)