The Philosopher King is a collection of philosophical reflections and exercises written by Roman Emperor Marcus Aurelius. The book explores the most important concepts of Stoic philosophy, including mortality, constant change, accepting the shortcomings of others, restraining oneself from the influence of fame and pleasure, and ultimately accepting the natural course of things and living according to nature. The book covers a wide range of topics, but there are a few key points that it continually returns to and builds upon, such as the importance of rational thinking, gaining perspective, and understanding one’s purpose.