If you have enjoyed this book, you will want these selected titles from the lists of

ACE BOOKS

D-327 FIRST ON THE MOON by Jeff Sutton

A novel of the life-or-death race between the U.S.A. and the U.S.S.R. for the conquest of space.

D-362 EDGE OF TIME by David Grinned Could they control another universe? and THE 100TH MILLENNIUM by John Brunner Search the past to learn the future.

D-35I THE SUN SMASHER by Edmond Hamilton Kidnapped to rule the stars! and STARHAVEN by Ivar Jorgenson Planet of the outcasts.

D-354 THE HIDDEN PLANET

Edited by Donald A. Wollheim Science-fiction adventures on Venus, by such as Chad Oliver, Leigh Brackett, Lester Del Rey, etc.

D-358 RECRUIT FOR ANDROMEDA by Milton Lesser Many had gone—none had returned. and THE PLOT AGAINST EARTH by Calvin M. Knox The clue was hidden in the stars.

35 < per nugpber

These books may be bought directly from Ace Books, Inc. (Sales Dept.), 23 West 47th St., New York 36, N. Y. Send the price indicated for each volume (adding 5<f. additional for handling). Order by Book Number.

THE INVADERS ARE COMING

BEWARE THE

MASTERS OF PANIC!

For a century America had been a securely isolated power without crisis, turmoil — or progress. Then suddenly super-security measures were shattered by the theft of fissionable metal from an atomic power plant. When it leaked out that the thieves had been invaders from outer space—alien monsters-chaos reigned.

The crisis called for a leader and the ruthless security chief, Julian Bahr, seized the helm, only to find everything he did strangely thwarted.

Was there an alien "Fifth Column" in his own organization?

Were the aliens already in control of the night skies?

Were his growing nightmares a new form of secret weapon?

Not until the last gripping page will you know the amazing secret that threatened America with total disaster. And by then you will have read one of the most outstanding, vividly exciting science-fiction novels ever written.

AN ACE BOOK