The police are meant to enforce the law and not abuse it. And yet the reality has been that policing and corruption are inseparable. This book sets out to explore that worrying but intriguing discrepancy between police as law enforcers and police as lawbreakers. Why do some officers bend and break rules, procedures and the law and why do some effectively become 'criminals'? And what measures should be taken to investigate, prevent and combat corruption?In seeking answers to such questions this book argues that corruption is not one thing but covers many deviant and criminal practices in policing which also shift over time. It rejects the 'bad apple' metaphor and focuses on 'bad orchards', meaning not individual but institutional failure. For in policing the organisation, the nature of work and its culture can sometimes foster and even encourage corruption. This raises issues as to why do police break the law and, crucially, 'who controls the controllers'?Corruption is defined in a broad, multi-faceted way. It concerns abuse of authority and trust; and it takes serious form in conspiracies to break the law and to evade exposure when cops can become criminals. Attention is paid to typologies of corruption (with grass-eaters, meat-eaters, noble-cause and the 'Dirty Harry' syndrome); the forms corruption takes in diverse environments; the pathways officers take into corruption and their rationalisations; and to collusion in corruption from within and without the organization.Comparative analyses are made of corruption, scandel and reform principally in the USA, UK and the Netherlands. The work examines issues of control, accountability and the new institutions of oversight such as the IPCC at a time when external oversight has become increasingly high profile. Overall the book provides a fresh, accessible and much-needed overview of this under-researched topic for students, academics, police and criminal justice officials and members of oversight agencies.