The Mystery of the 15 Sounds is a juvenile mystery novel similar to The Hardy Boys written in the 1930's. Roger works in his uncle Grover's laboratory. The laboratory does research for various companies and scientists. As a result of a bizarre series of events, Roger becomes involved in a mystery surrounding a missing sacred Tibetan jewel. Using science, Roger and his uncle solve the mystery and nab the bad guys in a scene straight out of a Scooby Doo mystery.
The author writes in a note before the story begins:
...every scientific device, process and theory herein is based on electrical, chemical and other data of developed apparatus and procedure or on theories so far perfected as to be acceptable to Science.
Very entertaining and a great garage sale find.