The books I use are enlarged and highlighted, so you can't get them anywhere else, their titles are unimportant to me. There are many thousands of such books from our past 200 years by many great authors, I suggest you pick and choose as you wish from the many, many websites that promote many old books.
I have seen so many people buy a book and get nothing from it, so I quit giving out my favorite authors names. There are enough free downloadable books on the web to keep people busy studying the rest of their lives. My little method is not for everyone. Eventually there may be a secure website to keep the crackpots out and on that I may make the books and study guides a great deal, until then they are only available from me in home made book form which is the most expensive way to put a book together.