Within the past five years, the scholarly literature on the U.S. Senate has been immeasurably enriched by the appearance of a half-dozen books that are noteworthy, not merely for the quality of the research involved but for the perspective they share. Directing their attention to different features of the institution, all emphasize what is truly distinctive about the Senate. In spite of powerful evidence that the hardedged partisanship that has long been a feature of the House has made strong inroads in the Senate, and in the face of evidence provided by Barbara Sinclair's Unorthodox Lawmaking (1997) and others that Senate leadership, at least in the postcommittee phase of legislation, has gotten more muscular in the manner of party leaders in the House, the two chambers are in no danger of becoming indistinguishable one from the other anytime soon.