The Rider's Perpetual contains 23 volumes of
schematics. For your information:
Other big collections of schematics for the USA
are the books «Most-Often-Needed Radio
Diagrams», compiled by M.N.BEITMAN (beginning:
1926-1938 = Vol. 1).
The Copyright notice in Rider's volume 14 is 1944.
But in the USA production of civil radios was
stopped End 1942. Therefore the latest models
contained are those of 1942. They also can be of
much earlier date.