 Corruption is a highly diverse phenomenon, including bribery, nepotism, false testimony, cheating, abuse of authority and so on. Moreover, corruption takes different forms across the spectrum of institutions giving rise to political corruption, financial corruption, police corruption, academic corruption and so on. The causal theory of corruption is a sustained attempt to provide an account which accommodates this diversity. In doing so it emphasizes the causal as well as the normative dimension of institutional corruption. The most influential contemporary philosophical theories of political corruption are those of Dennis Thompson and Lawrence Lessig. Moreover, Lessig’s notion of dependence corruptions looks to be generalizable to a degree to institutions other than political institutions. Likewise the mechanism that lies at the heart of Thompson’s theory may be generalizable to a degree to institutions other than political institutions. However, as they stand, neither of these theories provides a general or comprehensive theory of institutional corruption (and Lessig’s theory, at least, is not intended to do so). The wide diversity of corrupt actions implies that there may well need to be a correspondingly wide and diverse range of specific anti-corruption measures to combat corruption in its different forms, and indeed in its possibly very different contexts. Recent decades have seen the rise of whole systems of anti-corruptions mechanisms encased in what are referred to as integrity systems. Here we can distinguish reactive from preventive elements of an integrity or anti-corruption system and, arguably, an effective integrity system should integrate reactive and preventive elements in an overall holistic system.