Spinoza's Ethics is without doubt one of the most exciting and contested works in philosophy. The primary goal of this work written in the austere geometrical fashion is, as it was of the Ancients, to teach how we should live, and it ends with an ethics in which the only thing good in itself is understanding; only that which hinders us from understanding is bad; and beings endowed with a human mind should devote themselves, as much as they can, to a contemplative life. The purpose of the present volume is to provide a detailed and accessible step-by-step exposition of the Ethics; in this Introduction, we want to present the outlines of the reasoning behind Spinoza's rather uncompromising ethical intellectualism and briefly designate the particular topics discussed in the ensuing chapters. It seems that any theory of good life inevitably makes some fundamental assumptions concerning what human beings are, and it can be seen as an important virtue of Spinoza's approach that these basic questions are tackled in a thorough and explicit manner. For Spinoza, to know what we are depends on knowing what the universe or God is, because Spinoza sees us as limitations in God or the universe. Our bodies have spatial limits and our understanding has limits in thought. In seriously thinking about our bodies, we have to conceive them as being embedded in a larger spatial whole, and in thinking about our minds, we clearly see that our intellects are limited, even defective.