Financial and investment professionals are particularly vulnerable to ethical wrongdoing. But what makes some blatantly violate ethical standards and even break the law while others behave highly ethically? This monograph sheds light on the psychology behind ethical and unethical behavior. It explores fascinating psychological insights into the characteristics of unethical personalities and the role of nonconscious attitudes in unethical decisions. It examines how group processes, leadership, and organizational reward systems can turn otherwise ethical persons into unethical persons, and it demonstrates how rationalization tactics, moral disengagement, and impression management are used to psychologically justify or conceal unethical actions. Fortunately, as the author shows, psychology also provides the key to a genuine ethics in the financial and investment industry.