Money enters politics in a number of ways. Some politicians use their position to enrich themselves by accepting bribes; others prioritize raising funds for their reelection campaigns; yet other politicians leave their position to go through the "revolving door", and work for the very special interests they were regulating while in office. In this book, I argue that politicians strategically solicit and use money in a way that advances their career goals, and that the legal and political environment of a country govern how money enters politics. I empirically demonstrate this strategic choice between bribes, campaign contributions, and revolving door jobs using micro-level evidence from India, Brazil, and the United States, as well as with a series of case studies from countries around the world. Finally, I show that how money enters politics has profound implications on the quality of democracy, for example by affecting voters’ attitudes, who wins elections, how well political accountability mechanisms work, and what kind of people run for office.