Alvin's Secret Code

The second Alvin Fernald novel, published in 1963 with line illustrations by Bill Sokol. Twelve-year-old Alvin and his friend Shoie turn a self-taught grounding in codes and ciphers into a full treasure hunt.

The two boys, calling themselves secret agents, intercept a coded message and cannot break it themselves. They seek out Mr. Link, a retired code expert, who teaches them cipher wheels, the scytale, and other classical methods. The arrival of a woman in distress and a mysterious stranger draws Alvin, Shoie, and Alvin's younger sister into a hundred-year-old town mystery and a scheme against a local orphanage. It ends in a hunt for buried treasure, which Alvin's "Magnificent Brain" resolves through his own improvised cipher. An appendix at the back lays out the codes, ciphers, and code wheel used in the story for readers to try themselves.

Clifford B. Hicks was a Popular Mechanics editor and a Silver Star-decorated Marine veteran of World War II. He introduced Alvin Fernald in 1960 with The Marvelous Inventions of Alvin Fernald. Alvin's Secret Code was the second of what grew into a long-running series, later adapted into two Disney television movies.