We have a real classic fom the History of Radio. In the 1930’s to mid 1940’s Rider published a book called “Servicing Superheterodynes”. You can find a real hardcopy on ebay. We have a PDF version.
At the time the first edition of “Servicing Superheterodynes” was published the superheterdynereceiver was first becoming generally known to the public. As the years passed, so did the tuned radio frequency set pass out of popular favor to be replaced by the well liked and today, well behaved, superhet. Today, everything is the superheterodyne… The few t-r-f receivers, which are still being produced, are completely overwhelmed by the number of receivers based on the heterodyneprinciples. And – if you please, these receivers are becoming more and more complicated daily.
– John Rider from the 1934 edition
And please, don’t forget this modern book by Richard McWhorter.
The PDF of the book is password protected.
The password is “allamericanfiveradio”