In the eyes of apologists such as William Gibson, technology is morally neutral. Even so, it has bequeathed some supremely slick and safe methods of dispatching enemies. Back in the days of poor personal hygiene, heavy brows and hairy backs (both sexes), if you wanted to eliminate somebody who was bothering you it took a great deal of personal commitment. Even if you were sophisticated, your best option was a sharpened flint. Otherwise, you just relied on a rock. The main drawback with this kind of simple but honest weaponry was that it obliged the user to stand close to the prospect, risking detection. What should be done? After many millennia of head-scratching, a technology emerged which meant you could ice multiple antagonists without the victims gaining an inkling of their impending doom. The technology in question is stealth. Stealth hinges on an ingenious technique called astrodiltronics which marries ideas from quantum physics, Heisenberg's Uncertainty Principle and the diaries of Leonardo da Vinci. Actually, the wonder of stealth is that, despite the mystery which shrouds it, anyone, no matter how slow and technophobic, can understand how it works with the help of a little background. Most modern aircraft have a rounded shape. On one hand, this makes them aerodynamic. On the other, it creates an efficient radar reflector. No matter where the radar signal hits the plane, some of the signal gets reflected back, which means curvaceous planes may as well drop leaflets saying target-practice time. A stealth aircraft, by contrast, consists entirely of flat surfaces and sharp edges. As a result, when a radar signal hits a stealth plane, it just glances off. In addition, surfaces on a stealth aircraft can be treated with substances which absorb radar energy. Consequently, a stealth aircraft like an F-117A looks about as threatening on a radar screen as a canary. Thanks to stealth, planes capable of dropping nuclear bombs can now fly invisibly into enemy airspace, deliver their payload, and fly back out without being identified (although presumably remaining invisible to your enemies is of minimal importance once you have nuked them). The principles of modern stealth technology arose under appropriately mysterious circumstances. Analysts are baffled about how the dream of a plane as invisible as dark matter made the leap to reality. Intractable problems that bedevilled research aircraft were suddenly solved in a flash, the results guarded zealously behind the reinforced concrete walls of the Pentagon. According to the conspiracy camp, a deal struck with alien scientists gave engineers the answers they needed to build these silent flying machines. And indeed many of the prototype planes were mistaken for UFOs. Thanks to the secrecy surrounding stealth technology materials, the truth may never emerge. That said, there is about as much hard evidence to support the conspiracy theory as for the idea that a Ferengi dreamed up the spellchecker and a Martian invented the Internet. Whatever the inspiration, the motivation is clear. Stealth came about in response to the United States military's need to foil the Soviet Union's formidable defence systems. Since the end of the Cold War, stealth has proved its worth time and again. During the first Gulf War, 56 Stealth Bombers flew more than a thousand missions, and were never hit. Likewise, in the Iraq War, not one Stealth bomber bit the dust. Costing US$2 billion each, stealth bombers have yet to become a must-have accessory for yuppies bored with their Hummer. Even so, eventually military forces around the globe will try to ape some of the key characteristics of stealth planes. The god-like allure of a machine that can strike like a thunderbolt without betraying its presence will surely prove irresistible to heavy-browed despots everywhere. Confused by computer jargon? E-mail firstname.lastname@example.org with your questions.