On Secret Service

II. The Mint Mystery

III. The Ypiranga Case

IV. The Clue on Shelf 45

V. Phyllis Dodge, Smuggler Extraordinary

VI. A Matter of Record

VII. The Secret Still

VIII. The Taxicab Tangle

IX. A Match for the Government

X. The Girl at the Switchboard

XI. "Lost-$100,000!"

XII. "The Double Code"

XIII. The Trail of the White Mice

XIV. Wah Lee and the Flower of Heaven

XV. The Man with Three Wives

XVI. After Seven Years

XVII. The Poison-pen Puzzle

XVIII. Thirty Thousand Yards of Silk

XIX. The Clue in the Classified Column

XX. In the Shadow of the Capitol

XXI. A Million-dollar Quarter

XXII. "The Looting of the C. T. C."

XXIII. The Case of Mrs. Armitage

XXIV. Five Inches of Death