Executive Summary Most recent work on the politics of interest representation assumes that lobbyists represent their clients' interests with fidelity. As a check on the validity of this assumption, we examine the potential for principal-agent problems to emerge in the relationship between lobbyists and clients. We first consider the nature of agency problems in lobbying, emphasizing problems of outcomes, interests and monitoring. Next, we examine market, hierarchical and social controls of agency problems in lobbying. We then discuss the implications of our analysis for studies of interest organization mobilization, tactics and strategies, and influence. And finally, we argue that renewed attention must be paid to the internal operation of interest organizations, a subject that has been given scant attention in recent research on interest representation.In 2006, lobbyist Jack Abramoff was convicted -along with two White House officials, US Representative Robert Ney, and nine other lobbyists and Congressional aides -of a range of crimes, including mail fraud and conspiracy. The Washington Post summarized one of the core elements of the case against Abramoff as follows:Washington lobbyist Jack Abramoff and public relations consultant Michael Scanlon quietly worked with conservative religious activist Ralph Reed to help the state of Texas shut down an Indian tribe's casino in 2002, then the two quickly persuaded the tribe to pay $4.2 million to try to get Congress to reopen it. Dozens of e-mails written by the three men and obtained by The Washington Post show how they built public r