In the contemporary scenario of sociological thought an increasingly central role has been played by a theoretical movement called analytical sociology. This is a very important attempt which reconnects to the kind of sociology that Robert Merton and Paul Lazarsfeld tried to develop at Columbia University after World War II. In the Oxford Handbook of Analytical Sociology, recently edited by Peter Hëdstrom and Peter Bearman, a middle range sociology is presented, following the Columbia tradition. But, strangely, the Handbook refers only to Merton as founding father of the Columbia tradition, and does not take into consideration Lazarsfeld’s contribution. On the contrary, the role played by Lazarsfeld in the beginning of generative models for explaining social phenomena is highly relevant. His attention towards the inter-subjective dimension of decision testifies his interest for phenomena generating mechanisms, also exemplified by his way of working, which refers to an analytical distinction between the concept of mechanism and that of process; a methodological distinction between causality and mutual effect; a conceptual assumption of different kinds of rationality, i.e. the idea that actors act reasonably and intentionally.