The present book deals with private corruption, that is, corruption in and between companies. It focuses on the subjective decision making processes of corrupt actors. Based on a thorough literature review on the corruption phenomenon focusing on private corruption, a perspective neglected up to now, the author derives the central research questions: What makes decision makers in companies act corruptly? Which motivational, volitional, emotional, and cognitive components do play a role? How does their interplay finally lead to corrupt action? To answer these questions, the author develops a model of corrupt action. It is empirically validated using an experimental simulation design that includes a business game. Moreover, the work examines the influence of a number of important personal and situational factors on the model of corrupt action. It gives a picture of the frequently used reasons for corrupt and non-corrupt behavior and outlines the most frequently used rationalization strategies of corrupt actors. The study does not only make a contribution to existing research, but also has important practical implications. The empirically validated model of corrupt action offers a useful tool for companies to derive suitable measures for the prevention and deterrence of corruption. The author gives recommendations for (human resource) management and some hints as to which measures may be used to influence the critical person-based determinants of corruption.