He has had unprecedented access to Mark Zuckerberg and Sheryl Sandberg for three years. And now renowned tech writer Steven Levy delivers the definitive history of one of America’s most powerful and controversial companies: Facebook.In his sophomore year of college, Mark Zuckerberg created a simple website to serve as a campus social network. The site caught on like wildfire, and soon students nationwide were on Facebook.   Today, Facebook is nearly unrecognizable from Zucke