The advancement of social theory requires an analytical approach that systematically seeks to explicate the social mechanisms that generate and explain observed associations between events. These essays, written by prominent social scientists, advance criticisms of current trends in social theory and suggest alternative approaches. The mechanism approach calls attention to an intermediary level of analysis in between pure description and story-telling, on the one hand, and grand theorizing and universal social laws, on the other. For social theory to be of use for the working social scientist, it must attain a high level of precision and provide a toolbox from which middle range theories can be constructed.