Though ‘evil’ is often used loosely as merely the generic opposite of ‘morally good’, used precisely it is the worst possible term of opprobrium available. In this essay it is taken as applying primarily to persons, secondarily to conduct; evil deeds must flow from the volition to do something evil. An evil action is one so horrendously bad that no ordinary decent human being can conceive of doing it, and an evil person is one who knowingly wills or orders such actions. Malignant evil—doing evil because it is evil—is not just possible but real, and is one of several kinds of evil delineated. There are incidental discussions of cruelty, Rosenbaum on Explaining Hitler, Baumeister on Evil, and Benn on wickedness. Footnotes1 Dedicated to Alan Gewirth, in honour of his 90th birthday, and in appreciation of his superb, illuminating, and ground-breaking philosophical work over many years.