Description: Questions about the characteristics of Members of Congress, including their age, education, previous occupations, and other descriptors, are of ongoing interest to Members, congressional staff, and constituents. Some of these questions may be asked in the context of representation, in efforts to evaluate the extent to which Members of Congress reflect their constituencies and the nation at large. In other instances, questions arise about how the characteristics of Members have changed over time, which may speak in part to the history of Congress. This report provides profiles of Senators and Representatives in selected Congresses since 1945. It includes data based on Representatives and Senators serving on the first day of the 79th, 82nd, 87th, 92nd, 97th, 102nd, and 107th–112th Congresses for several demographic characteristics, as well as the tenure of Member service in Congress. The characteristics discussed include age, including the oldest and youngest Members of the House and Senate; congressional service tenure; sex; previous occupation; race and ethnicity; education; religion; and military service.