Almost 90 years after Albert Einstein first postulated his general theory of relativity, Physisists have finished collecting data that will put his theory to a new and different kind of experimental test. NASA's Gravity Probe B, orbiting at an altitude of 400-miles directly over the poles, will measure two important effects: 1)how space and time are warped by the presence of the Earth and 2) how the Earth's rotation drags space-time around with it. These effects, if indeed they can be measured, have far-reaching implications for the nature of matter and the structure of the Universe.