In 1967, astronomers began receiving and cataloging precisely timed radio pulses from extraterrestrial sources, which they called pulsars. These pulsars emit laserlike radio beams that penetrate through space much like search-light laser beams. Paul LaViolette, who has been researching pulsars for over twenty-five years, shows that while these pulsars have long been assumed to be spinning stars, the true nature of these radio sources has been grossly misunderstood. In this captivating book, LaViolette shows that pulsars are distributed in the sky in a nonrandom fashiopn, often marking key galactic locations, and that their signals are of intelligent origin. Using extensive scientific data to corroborate his theory, he presents evdence of unusal geometrc alignments amont pulsars and intrguing pules-period relationships. Equally compelling is the message LaViolette contends is being sent by these extraterrestrial beacons: a warning about a past galactic core explosion disaster that could recur in the near future.