This article reconsiders the importance of including policy issue content and legislative significance in our study of lawmaking. Specifically, it demonstrates theoretically why lawmaking might vary by policy substance and empirically shows how incorrect conclusions would be drawn if lawmaking is studied by pooling enactments instead of disaggregating laws by policy issue content. It accomplishes this by bringing new tools, including a policy classification system and a way to measure the significance of public laws, to help overcome an array of measurement-related problems that have stymied our ability to better understand lawmaking. The policy coding schema introduced is applied, by careful individual human coding, to every public law enacted between 1877 and 1994 (n = 37,767). The policy issue and significance data are used to construct a number of new measures of legislative performance and are useful to test hypotheses within studies of Congress and American Political Development.