Druckerman asserts that there are stages to becoming a grown-up: First, you definitely aren't one. Then you pretend to be one. Then you are sure that there are no grown-ups. And then finally, maybe one day in your forties, you just are one. It's not all-knowing, omnipotent and large; it's humble, solid and small. But at long last, it feels like you. And you think, just then, that this is the best age of all. Explore the challenges of being fortysomething,...