Second Ace mass-market edition.
353 pages ; 18 cm
"Revised and with a new foreword"--Cover.
"From a remote corner of the galaxy a message is being sent. The continuous beats of a pulsar have become odd, irregular...artificial. It can only be a code. Frantically, a research team struggles to decipher the alien communication. And what the scientists discover is destined to shake the foundations of empires around the world--from Wall Street to the Vatican."-- Back cover.