For thousands of years humankind has speculated on the existence of planets and life beyond the solar system, but until recently astronomers have had only our own planetary system to study. Everything changed in 1995, however, when Swiss astronomers announced the first convincing evidence for a planet---though one very different from the Earth---orbiting a Sun-like star. In the past fifteen years, hundreds of planets have been found around other stars. The ultimate goal is to find Earth-like planets that could sustain life.