... a plaintive keening from an unknown voice in the vastness of uncharted space. Within hours the whole world had heard the strange, unearthly music—and the panic had begun.
Were the sounds a plea for help? From whom? From where? Or were they a command too terrible to think about? No one knew. And in billions of earth-bound minds the horror grew....
For how could man, who had not yet claimed the moon, defy a challenge from the stars?
And hours later, to the ears of a helpless world, the second message came....
And Earth's days were numbered!
A terrifying tale of tomorrow—or maybe tonight—by the undisputed master, Mr. Science-Fiction himself!
Other Avon books by:
MURRAY LEINSTER:
The Planet Explorer
Monsters and Such
Twists in Time
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