Following the success of her bestseller "The Book of Kale, " Sharon Hanna is back, teaming up with gardening editor Carol Pope for "The Book of Kale and Friends." There are good reasons why the Kale Revolution is growing -- this humble leafy green is one of the healthiest vegetables on earth, it thrives in winter and sweetens in the cold, it self-seeds, its flowers sustain bees, and it's so easy to grow that anyone who tries will feel like a master gardener with almost no effort.