Ethics or moral philosophy is a branch of philosophy that involves systematizing, defending, and recommending concepts of right and wrong conduct. The term ethics derives from Ancient Greek ἠθικός (ethikos), from ἦθος (ethos), meaning 'habit, custom'. The branch of philosophy axiology comprises the sub-branches of ethics and aesthetics, each concerned with values.
Practical Ethics (1979; second edition 1993; third edition 2011) is an introduction to applied ethics by bioethical philosopher Peter Singer. The book, which has been translated into a number of languages, caused outrage in German-speaking countries.