In the summer of 1940, with the Battle of Britain raging and a German invasion imminent, Winston Churchill took a dramatic step: authorizing the disclosure of critical scientific breakthroughs to the U.S. in hope their ally could make them available for wartime use. The mission became known as the Tizard Mission, after the well known British radar scientist who led the effort.
The scientific instruments were carried in a large black box and demonstrated to both scientific and military personnel over a three week period. Included in the box was a cavity magnetron, a high-powered vacuum tube that generated microwaves capable of identifying objects down to ten centimeters. The magnetron was far ahead of anything then under research in the United States, and was immediately recognized for its potential to alter the course of the war.
Through these meetings, the U.S. and Britain agreed to setup a laboratory to drive the research of radar based on the magnetron. The result: the Radiation Laboratory on the MIT campus ("RAD Lab"). By December 1940, a basic working radar was being tested on top of Building 6 at MIT. Over the next five years, the laboratory grew to include over 3,500 employees and produced the designs for 100+ radar systems essential to the war effort. Many historians attribute radar as the single most important technology responsible for the Allies winning the war.
The Tizard Mission was in many ways the spark that lit the fire of Boston high tech, resulting in the first of a series of government-funded wartime research investments in the Boston area. The result: a highly skilled technical workforce that would become the germinating seed for our current high tech landscape.
I've been on a high tech history reading binge this summer. Some of the more interesting books include Crystal Fire, ENIAC, Dealers of Lightning, The Man Who Invented the Computer, and Turing's Cathedral (mixed feelings about this last one though).