Did they know how to write a good manual back then. You've got your soldering primer, guides on how to use test equipment... heck, you can probably apply some of the mechanical knowledge to fix your kitchen sink.
It says in the preface that 'the book' will not turn you into a technician but I've seen some 'technician course materials' that couldn't hold a candle to this one publication.
Very nice to see this preserved.