The Daily Stoic: 366 Meditations on Wisdom, Perseverance, and the Art of Living

by Ryan Holiday

If we can focus on making clear what parts of our day are within our control and what parts are not, we will not only be happier, we will have a distinct advantage over other people who fail to realize they are fighting an unwinnable battle.

This is the best and clearest example of what stoicism is if you are asked to define it.