Twenty-five years ago, as I headed out on my first expedition, I had a lot of questions. In Rules to Live By, New York Times bestselling author, National Geographic photographer, and Academy Award–winning filmmaker of Free Solo Jimmy Chin turns to ten icons who have helped him think more deeply about how we choose to live, how we endure, and, in the end, what really matters. I’ve found a few answers since, but one question remains: In the end, what really matters? A few fundamental truths are worth examining again and again, because we evolve and so does our understanding.