The Mystery of the 15 Sounds is a juvenile mystery novel similar to TheHardy Boys written in the 1930's. Roger works in his uncle Grover'slaboratory. The laboratory does research for various companies andscientists. As a result of a bizarre series of events, Roger becomesinvolved in a mystery surrounding a missing sacred Tibetan jewel. Usingscience, Roger and his uncle solve the mystery and nab the bad guys in ascene 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 onelectrical, chemical and other data of developed apparatus andprocedure or on theories so far perfected as to be acceptable toScience.
Very entertaining and a great garage sale find.