This chapter starts with an overview on ethical and eco nomic theory. For ethics it relates some main classes of theory, i.e. virtue ethics, utilitarianism and contractarianism. Concerning eco nom ics the focus is on microeco nom ics and game theory. Then the im port ant distinction between eco nomic ethics and business ethics is highlighted and related to the current liter at ure. More over, order ethics is illus trated as a well-established interface of ethics and eco nom ics. This theory is then related to the central theme of this book, i.e. beha vi oural eco nom ics including game theory and experimental methodology.