A majority of what we know about congressional elections comes exclusively from the study of the House of Representatives. This dissertation seeks to fill a significant hole in that literature by asking important questions about congressional elections in the context of the Senate. Using data from 1914 to 2010, I am able to present patterns and trends over time in the study of Senate elections. In Chapter 1, I provide a brief overview of the study of Senate elections as well as the central research questions in this dissertation. In Chapter 2, I examine who runs for the Senate. In addition to this question, I examine the suitability of various measures of candidate quality. I find that the dichotomous measure of candidate quality, first employed by Jacobson, performs similarly to more complicated scales and ranking procedures typically used in the Senate. In Chapter 3, I address the question of whether or not incumbent Senators are able to ward off quality challengers by amassing a sizeable campaign war chest. I find that, with proper measurement, incumbents are able to prevent the emergence of a quality challenger. Finally, in Chapter 4, I turn to one of the most studied questions in congressional elections research. The question of why incumbents are reelected at such a high rate has yielded a substantial literature in the House, but little attention in the Senate. Using methods first used in the House, I find evidence of an incumbency advantage in the Senate since the 1950s. In addition, I find that trends in the growth of the incumbency advantage mirror patterns found in the House. In the concluding chapter, I summarize the findings of this dissertation as well as offer suggestions for future research.