The concept of economic rent is among the oldest in political economy. This reflects the fact that economies have always included parties whose income appears more parasitic than productive. The concept of rent-seeking refers to the efforts of parties seeking to secure such income by way of gaining influence over economic regulation or otherwise gaining favors from government. In spite of its intuitiveness, however, it has proven difficult to precisely distinguish rent from other categories of income. This chapter seeks to acquaint readers with this problem. The privatization of incarceration is then supplied as an important case study in current rent-seeking behavior.