As a retired four-star general, Stanley McChrystal might be measured by his stars (four), commands held, wars fought, or awards and medals received (numerous). But when McChrystal looked back on his life and his current status, he focused on the importance of character, a topic he explores in his new book aptly titled On Character: Choices that Define a Life. Character is, he says, the key to living with purpose and integrity. He says character isn’t something you are born with, but the result of a succession of choices, sometimes mundane ones, sometimes hugely important ones, that together reveal our capacity for virtue.