Hi there, I would like to study FS and read books and articles on the FS websites. Almost all what I found is very descriptive (what is a good or bad FS) but my search for the whys and wherefores is pretty much unfulfilled. Which are the books, which really go in depth? Also, I want to find books, which teach you how the use the FS compass and its 30 tiers. Thank you for your help Stephane