I used to have a book that traced the history of books which had titles like "secrets of the universe explained", "secrets of chemistry exlained", or "secrets of magic revealed", etc. The author claimed that with the invention of the printing press a category of books of "secrets" proliferated. Today, we still see books revealing secrets of the universe.
So, this type of "secrets" books appears to be a genre.
Does anyone know this book? It is probably from 1980s or '90s.
Thanks.