The principles underlying radio communication
While digging around for some information on crystal radios on the Internet (since i seemed to have misplaced the book on the subject I was looking for) I encountered some references to a book which happened to have been digitized and made available on archive.org. This book was published by the National Bureau of Standards, and no less of a luminary than Thomas Edison wrote:
This is the greatest book on this subject that I have ever read, and I want to congratulate you and your Bureau on its production.