I'm not sure if this has been posted before. I had this bookmarked a while back but lost the link when my computer crashed. I only recently found it again in a backup file and decided to share.
There is an amazing amount of vintage books on electronics, audio, radio, science, etc. available to read online. Including a Gernsback bookshelf full of material that I poured over as a young boy. I hope you find this treasure trove useful or entertaining.
https://worldradiohistory.com/index.htm
