Taking on technology: Eight new books look at our wired world

Twitter is 7 years old; Facebook is 9; Google, 15; Amazon, 19, and Apple, 35. These transformative companies have been around long enough, and have become so essential that, all at once, there is a flurry of books about them. It can't hurt that Walter Isaacson's biography of Steve Jobs was a massive bestseller; in almost each case, authors look at the people behind the tech companies to explain how they do what they do. Here's a look at what's hitting bookstores now.