I	"For Uncle Sam"	[9]
II	Into the Service—A Spy	[21]
III	Unexpected Action	[34]
IV	Farewell, United States	[43]
V	The Fight in the Wireless Room	[54]
VI	The Mystery of the Iron Cross	[67]
VII	The Timely Rescue	[77]
VIII	The Death of the Spy	[88]
IX	The Periscope at Dawn	[101]
X	France at Last	[110]
XI	Tapping the Enemy's Wire	[118]
XII	The S O S With Pistol Shots	[131]
XIII	The Cave of Death	[140]
XIV	DESPERATE MEASURES	[153]
XV	The Surprise Attack—Promotion	[164]
XVI	A Tight Place	[176]
XVII	The Lieutenant's Invention	[191]
XVIII	Slim Goodwin a Prisoner	[200]
XIX	Turning the Tables	[211]
XX	The Great News	[221]

Illustrations

"At Least Ten Thousand of Them," He Announced.	[Frontispiece]
There was an Instant of Terrible Whirling about the Room.	[66]
Scores of Huge Armored Tanks Rolled Through	[168]

The Brighton Boys in the Radio Service