WiFi has made our communication technology truly mobile. Today, we can check our emails or log on to an Internet site at a cafe, train station or an airport - anywhere, infact, where WiFi is available. Learn how the world became wireless and how that changed both the way we work and the way we have fun. Find out more about how WiFi works and how this high-tech science has brought freedom to your world.High-Tech Science is a series of four books that look at the revolutionary, cutting-edge science that we rely on to run our lives and keep our modern world working.