Written by Benedict de Spinoza, The Ethics (originally published in 1677) is a philosophical treatise which covers and attempts to apply the method of Euclid. In that vein, de Spinoza discusses issues like the nature of God, how man's mind works, human emotions and how people deal with them, and how empathy and understanding are powerful aspects of humans and their humanity. The Ethics, in essence, is a philosophical reflection discussing incredibly complex ideas and issues.
The Ethics is widely considered de Spinoza's best work and received positive reviews upon its release. A blogger for the Baha'i Chair for World Peace, for example, loved the book, writing that the book is "profound" and that "Of course, there is much more to say about why The Ethics was such an interesting and difficult book to read. But foremost this ‘Copernican revolution’ that Spinoza offered is something that I will have to think about again and again."