August 1, 2007: Since the war on terror began, U.S. spending on classified projects has nearly doubled, to $32 billion. These "black" projects began during World War II. The most prominent one back then was the "Manhattan Project," the $22 billion (in current dollars) effort to develop and build atomic bombs. The reason for keeping the "Manhattan Project" secret was the fear that any knowledge of the American research would make it easier for the Germans to develop the bomb, and do it first. Before World War II, no one was sure a nuclear weapon could be built. Knowledge of what the U.S. was doing, and how much it was spending, would have provided the Germans with valuable information on the possibility of building nukes.

After World War II, especially when the Cold War began in the late 1940s, there were a lot more new military technologies that were useful to the enemy even if they just knew you were working on them, and how much you were spending. So black projects continued to get funded, and shrouded in secrecy. The most obvious of these were the ones involving aircraft, like the F-117 and B-2 stealth bombers. But there were many more projects involving spy satellites, nuclear weapons and all manner of electronic devices. The air force has traditionally gotten most of the "black" money. Currently about 40 percent of the air force research and procurement budgets. Overall, about 60 percent of black money is for research, the rest for procurement. We could tell you more, but it's all classified.