One of the most important philosophical works of all time, in a new Penguin Classics translation. Aristotle's classic treatise is based on his famous doctrine of the golden mean, which advocates taking the middle course between excess and deficiency. Reacting against Plato's absolutism, Aristotle insisted that there are no definitive moral standards, and that ethical philosophy must be based on human nature and experience. Treating such topics as moral worth, intellectual virtue, pleasure, friendship, and happiness, Aristotle's work asks above all: what is the good life and how can we live it?