Despite critical attention, Black's (1976)The Behavior of Lawhas been subjected only to limited empirical research, mostly at the microsociological level. These studies have at best provided mixed support for Black's thesis. The present study offers a more extensive, macrosociological test of his five major propositions through analysis of aggregate-level data for the U.S. from 1948 to 1985. We examine four models of longitudinal changes in the quantity of law as a function of levels and changes in levels of the aspects of social life addressed by Black. As with previous studies, our findings offer limited support for Black's propositions. The majority of the relationships investigated do not behave as Black has posited. We offer an extended discussion of two of the more consistent findings: the relation of organization to change in law and the lack of a relationship between morphology and change in law.