The scholars who write in the following pages have thought seriously about the implications of using historical data, of retesting old hypotheses, of formulating new ones. In an era when professional historians seem to have abandoned political history, congressional scholars are clearly taking up the slack. On a case by case basis, the results of this scholarship encourage us to rethink various parts of our conventional wisdom about the Congress. More generally, however, these scholars and their like-minded colleagues are virtually requiring that an entire subfield of American politics think about the institution of the Congress in different ways than we often have in the past. The cross-fertilization of research techniques, theoretical perspectives, and data collection will energize the study of congressional politics for a long time to come.