Nicomachean Ethics. by Aristotle

Aristotle examines how best to live by looking at the nature of those virtues that characterize the most thriving human beings, and then at how to acquire and develop such virtues. This book is considered the founding document of what is now known as the "virtue ethics" tradition. Along the way, Aristotle delves into pleasure, happiness, justice, friendship, and willpower. He intended the Nicomachean Ethics to be the foundation on which to build his Politics.
Nicomachean Ethics is based on Aristotle's lectures at the Lyceum and was originally collected as a series of ten scrolls. In translation it was hugely influential in the development of Western philosophic tradition, quickly becoming one of the core works of medieval philosophy.