Clifford B. Hicks fans, who have eagerly awaited a new Alvin Fernald story, will find this latest offers a wonderful adventure, told with humor and suspense, plus the added attraction of some fascinating information on coding activities young people will enjoy doing themselves.

Here again is Alvin, the Magnificent Brain (now known as Secret Agent K 21½ ), and his best friend, Shoie, who find this secret message one day after school:

SERIOUS MILLY HIDING THURSDAY.
START SECRETS. IVAN HIDING
MESSAGE OAK. REMAIN SILENT.
                              HERMAN

The boys' efforts to break this code take them to Mr. Link, a former spy, who teaches them all about ciphers and code wheels and scytales. The arrival, in town, of a lady in distress and a mysterious stranger soon lead the two (joined by Alvin's sister, the Pest) to a dangerous test of their new-found knowledge.

How Alvin routs a villain with a most original scheme, rescues the fortunes of an orphanage, and leads the entire town on a hunt for buried treasure, is revealed in the climax to this exciting tale, handsomely illustrated by Bill Sokol.

From the dust jacket