Triple Spies

Roy J. Snell (1878-1959) authored at least 85 Young Adult novels under his own name and as by David O'Hara, James Craig, and Joseph Marino, most of them specifically directed to boys, though he wrote at least one series of mysteries for girls. His tales for younger children, beginning with Little White Fox and his Arctic Friends (1916), are animal fantasies.

This series consists of:

1. Triple Spies
2. Lost in the Air
3. Panther Eye
4. Crimson Flash
5. White Fire
6. Black Schooner
7. Hidden Trail
8. The Firebug
9. Red Lure
10. Forbidden Cargoes
11. Johnny Longbow
12. The Rope of Gold
13. Arrow of Fire
14. Riddle of the Storm
15. The Galloping Ghost
16. Whispers at Dawn
17. Mystery Wings
18. Red Dynamite
19. The Shadow Passes
20. Sign of the Green Arrow