I was on amazon a few days ago, simply browsing--and looked up books by Martin Grams, Jr., who has been referred to a number of times in this space. (He has written many books, over time, about classic radio and television shows.)
I learned about a title he has coming out in November, written with : The Top 100 Radio Shows of All Time (Portable Press). Am looking forward to reading it.
https://www.amazon.com/Top-100-Radio-Shows-Time/dp/1684121272/
http://www.martingrams.com/