Considered the gold standard on interest group politics, this book analyzes interest groups within the intuitive framework of democratic theory. Readers gain an understanding of the workings of interest groups within the larger context of our political system. Comprehensive coverage includes not only the traditional farm, labor, and trade associations, but also citizen groups, public interest organizations, corporations, and public interest firms. This sixth edition of the text updates the role of money in interest group activity following the Citizens United Supreme Court decision. The authors also cover new interest group actors including the Tea Party, Occupy, and others, examine new developments in key interest group arenas including health care and the environment, and look at the role of social media in interest groups. A comparative look at interest group action, organization, and scholarship abroad has also been added.