First published posthumously in 1677, "The Ethics" (AKA Ethics, Demonstrated in Geometrical Order) is a philosophical treatise written in Latin by Benedict de Spinoza (Baruch Spinoza)..

"The Ethics" is an ambitious and multifaceted work. Ambitious in its subject matter because Spinoza criticizes all traditional philosophical conceptions of God, man and the universe. Ambitious also because Spinoza's method is to demonstrate the truth about God, about nature, man, religion and the good life. Indeed, Spinoza proceeds by means of definitions, axioms, corollaries and scholia, that is, mathematically.

Although Spinoza's Ethics embraces theology, anthropology or ontology and metaphysics, he chose the term "ethics" because he postulates that happiness comes from a liberation from superstition and the passions. In other words, he sees ontology as a way of demystifying the world and enabling man to live according to reason.