ts reserved. This book, or any part thereof, may not be
reproduced in any manner without written permission of the publisher,
except for brief quotations embodied in critical articles or reviews.
For information, address: SHASTA PUBLISHERS, 5525 South Blackstone
Avenue, Chicago, 37, Illinois.

_Copyright, 1953, by Will F. Jenkins. This POCKET BOOK edition is
published by arrangement with Shasta Publishers. Printed in the U.S.A._

* * * * *

[Illustration: Pocket Book]

_Notice_: POCKET BOOK editions are published in the United States by
Pocket Books, Inc., in Canada by Pocket Books of Canada, Ltd., and in
England by News of the World, Registered User of the Trade Marks. Trade
Marks registered in the United States and British Patent Offices by
Pocket Books, Inc., and registered in Canada by Pocket Books of Canada,
Ltd.

ACKNOWLEDGMENTS

This acknowledgment is necessary if I am to say thanks to some experts
to whom I am indebted. There is Captain Charles Benjamin, who read over
the aviation parts of this book with pursed lips and a belligerent
attitude toward questionable statements of fact or observation. There is
Dr. John Drury Clark, whose authoritative knowledge of rocket fuels was
the basis for admitted but not extravagant extrapolation on my part.
There is the crew of a four-engined transport ship, who argued over my
manuscript and settled the argument by a zestful, full-scale
crash-landing drill--repeat, "drill"--expressly to make sure I had
described all the procedure just right. There is Willy Ley, whom I would
like to exempt from responsibility for any statement in the book, while
I acknowledge the value of personal talks with him and the pleasure
anybody who has ever read his books will recognize. And there is Dr.
Hugh S. Rice of the Hayden Planetarium, who will probably be surprised
to find that I feel I owe him gratitude. They are in great part
responsible for the factual matter in this book.

I think I may add, though, that I worked on it too.

MURRAY LEINSTER
"Ardudwy"
Gloucester, Va.

_Space Platform_

1

There wasn't anything underneath but clouds, and there wasn't anything
overhead but sky. Joe Kenmore looked out the plane window past the
co-pilot's shoulder. He stared ahead to where the sky and cloud bank
joined--it was many miles away--and tried to picture the job before him.
Back in the cargo