Against the background of religious wars and in full knowledge of the relevance of the new exact sciences of the the seventeenth-century, Spinoza developed one of the most ambitious projects in the history of philosophy: his Ethics written in geometrical style. It is a book that deals with ontology, epistemology, human emotions, as well as with freedom and bondage of individuals and societies, in one continuous line of argument. At the same time, the book combines the highest standards of conceptual and argumentative clarity with a wisdom that is saturated with the experience of life. Even today it sets a standard for enlightened theoretical and practical reasoning. This collective commentary discusses all five parts of Spinoza's Ethics. In the introduction, historical consequences of the Ethics are elucidated, as well as its continued philosophical relevance.