[c] by Grosset & Dunlap, Inc., 1961 All Rights Reserved Printed in the United States of America
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CONTENTS
Chapter Page
1 The Earthquake 1 2 The Mysterious Hitchhiker 11 3 Report from Interpol 18 4 Another Tremor! 30 5 Secret Cache 39 6 Brungarian Coup 46 7 Wall of Water! 55 8 A Suspect Talks 65 9 The Cave Monster 73 10 Energy from Planet X 83 11 An Electrical Christening 92 12 Exman Takes Orders 99 13 Disaster Strikes 106 14 Air-borne Hijackers 115 15 Kidnaped! 125 16 A Unique Experiment 137 17 An Urgent Warning 145 18 Earthquake Island 155 19 A Fiendish Machine 166 20 The Robot Spy's Story 177