1985 NY: Tor  First edition, first printing, fine in fine dustjacket, signed by author.

A small cube of black rock has been unearthed in a 3500-year-old Mycenaean tomb. An incomprehensible object in an impossible place; its age, its purpose, and its origins are unknown. Its discovery has unleashed a global storm of intrigue, theft and espionage, and is pushing nations to the brink of war. Its substance has scientists baffled. And the miracle it contains does not belong on this Earth.

It is mystery and madness -- an enigma with no equal in recorded history. It is mankind's greatest discovery ... and worst nightmare. It may have already obliterated a world. Ours is next.