| # | Book Title | Author | ||
|---|---|---|---|---|
| 15 | Mystery of the Flaming Footprints, The | Carey, M. V. | ||
| 17 | Mystery of the Singing Serpent, The | Carey, M. V. | ||
| 20 | Mystery of Monster Mountain, The | Carey, M. V. | ||
| 21 | Secret of the Haunted Mirror, The | Carey, M. V. | ||
| 23 | Mystery of the Invisible Dog, The | Carey, M. V. | ||
| 24 | Mystery of Death Trap Mine, The | Carey, M. V. | ||
| 27 | Mystery of the Magic Circle, The | Carey, M. V. | ||
| 29 | Mystery of the Sinister Scarecrow, The | Carey, M. V. | ||
| 31 | Mystery of the Scar-Face Beggar, The | Carey, M. V. | ||
| 32 | Mystery of the Blazing Cliffs, The | Carey, M. V. | ||
| 34 | Mystery of the Wandering Cave Man, The | Carey, M. V. | ||
| 36 | Mystery of the Missing Mermaid, The | Carey, M. V. | ||
| 39 | Mystery of the Trail of Terror, The | Carey, M. V. | ||
| 41 | Mystery of the Creep-Show Crooks, The | Carey, M. V. | ||
| 43 | Mystery of the Cranky Collector, The | Carey, M. V. |