In the early days of World War II, British scientists had just completed what would be the most advanced defense system of their day: a network of radio-signal stations that could detect the approach of Nazi bombers, day or night, in fair or foul weather. This network was given the ungainly title "Radio Detection and Ranging" but is most commonly known as radar. Though the list of scientists who contributed to its creation is long, the name at the top would certainly be Sir Robert Watson-Watt, whose work made the creation of radar possible. Watson-Watt was born on April 13, 1892, and as a student in Brechin, Scotland, he developed an interest in radio telegraphy; in 1915 he began working for the London Meteorological Office using radio waves to monitor thunderstorm activity, an essential task to aid the safe flight of early fragile aircraft. He continued to work for the government...