This book focuses on the important work of Karl Mannheim by demonstrating how his theoretical conception of a reflexive sociology took shape as a collaborative empirical research program. The authors show how contemporary work along these lines, whether derived from Foucault, Bourdieu or other theorists, can benefit from the insights of Mannheim and his students into both morphology and genealogy.Inspired by recent receptions of Karl Mannheim that do not restrict themselves to familiar arguments about the sociology of knowledge, the book contains three themes. First it offers a new reading of Mannheim's 'empirical' project, with emphasis on his lifelong dialogue with Max Weber. Special attention is paid to his article on 'economic ambition.' Second, the book analyzes the work arising out of Mannheim's Frankfurt research group, notably the early writings of Norbert Elias, Hans Speier, and Hans Gerth, as well as dissertations by Mannheim's students, including studies of newspapers, women's household roles, sentimentalism in women's literature, relations between female social workers and male bureaucrats, exile, Jewish assimilation, and Liberal 'cultivation.' Finally, the book contributes to the microsociology of knowledge, uncovering the modalities that made for an open working group in Frankfurt that was expressly not a school.The book returns Mannheim's sociology of knowledge inquiries into the broader context of a wider project in historical and cultural sociology, whose promising development was disrupted and then partially obscured by the expulsion of Mannheim's intellectual generation. It is about Karl Mannheim as he served his most productive - and independent - students and not as he has been stereotyped in the literature. As such, it will appeal to sociologists concerned with the contemporary relevance of his work, and who are prepared for a fresh look at Weimar sociology and the legacy of Max Weber.