Millions of people look to Tim Ferriss, author of The 4-Hour Workweek, for advice about how to live their lives better. So what advice has he learned to give himself during this tumultuous year? Forget trying to maintain the illusion that you can control everything. Instead, learn from the Stoics, and look to what you can control — your inner life and your reactions. Tim speaks with Arianna Huffington about gratitude, sleep, meditation and self-care.