Project Gutenberg has millions of public domain books which are free for everyone. These are books whose copyright period has completed. You can always find a great book in the list. Check out the books here https://www.gutenberg.org/browse/scores/top
Get The Almanack of naval ravikant for free ( resource 2)
Naval is giving his great book for free on his website for a long time. You can get the book by the link below https://www.navalmanack.com/
Nonfiction books lessons tool ( resource 1)
Record main lessons and stories used to explain those lessons in an easy to retrieve format. You can make a docx file like this. You can print this if you want handwritten notes I have used it for long. Makes an archive of great book lessons. It can be used to revise great nonfiction books.