The Ethics is a philosophical book written by Baruch Spinoza. It was written in Latin. Although it was published posthumously in 1677, it is his most famous work, and is considered his magnum opus.
In The Ethics, Spinoza attempts to demonstrate a "fully cohesive philosophical system that strives to provide a coherent picture of reality and to comprehend the meaning of an ethical life. Following a logical step-by-step format, it defines in turn the nature of God, the mind, human bondage to the emotions, and the power of understanding -- moving from a consideration of the eternal, to speculate upon humanity's place in the natural order, freedom, and the path to attainable happiness. (Wikipedia)