The Enchiridion

"Of things, some depend upon ourselves, others do not depend upon ourselves." This simple opening line of The Enchiridion (c. 125 CE), the defining handbook on stoicism, contains Epictetus’ entire philosophy boiled down to its most essential: control what you can control and do not concern yourself with what you cannot.

A direct influence on legendary thinkers like Marcus Aurelius, Epictetus prescribes constant vigilance for the burgeoning stoic. Vigilance not just of the physical world, but...