In the fall of 1959, Giuseppe Cocconi and Philip Morrison published a paper in Nature that ended in the sentence, “The probability of success is difficult to estimate; but if we never search the chance of success is zero.” Frank Drake had reached similar conclusions, and in the spring of 1960, with the blessing of two directors of the National Radio Astronomy Observatory, he used the 85- foot Tatel radio telescope to conduct Project Ozma. Drake observed two nearby stars (Tau Ceti and Epsilon Eridani) for several hundred hours with a single-channel, narrow band receiver, and the scientific exploration known as SETI (Search for Extraterrestrial Intelligence) was born. Today, SETI observations take place at optical wavelengths in addition to radio. Broadband optical signals that are compressed in time (laser pulses) are sought with arrays of photodiodes having nanosecond rise times, and narrowband radio signals are pursued with billion-channel spectrometers and a global network of distributed computers. An innovative radio telescope array has been added to the world’s inventory of scientific instrumentation allowing commensal SETI and traditional astronomical surveys continuously. After millennia of asking the priests and philosophers what to believe, it is now possible to make observations to try to answer the old question, “Are we alone?” It is time to look back on the first 50 years and consider what might happen in the next 50 years.