Kentucky has produced scores of influential senators, including two Senate majority leaders and one of the nation's greatest lawmakers, Henry Clay. These Kentuckians played an important role in the evolution of leadership institutions in the Senate. Official positions of power such as Senate majority leader are nowhere to be found in the Constitution or early American history, yet today these offices have essentially eclipsed the constitutionally created legislative leadership positions of vice president and president pro tempore. While Kentucky senators have played a vital role in leading the Senate and in its institutional history, no book has told the story in its entirety. The US Senate and the Commonwealth: Kentucky Lawmakers and the Evolution of Legislative Leadership is the first book of its kind to provide a detailed, yet accessible discussion of the US Senate's leadership throughout its 225-year history. Senator Mitch McConnell and Roy E. Brownell II achieve this level of detail by weaving together the history of the Senate with lively portraits of prominent Kentucky senators as well as McConnell's firsthand reflections about legislative leadership as the current Senator majority leader. The authors illuminate and humanize this discussion by exploring the colorful and vivid lives of fifteen Kentucky lawmakers, including Henry Clay, Joseph C. S. Blackburn, and Alben Barkley. This work also provides the first extended, published treatment of the lives of a number of Kentucky senators -- including John Brown, John W. Stevenson, Earle Clements, and Wendell Ford -- many of whom are largely forgotten today despite their past prominence.