All the books are low information for me, because I live in Florida. I've not read *any* bonsai books, including ficus ones, that have been much use.
Buy yourself Bonsai Today issues #1-#4, or the whole entire set. Once you learn how to properly wire, properly carve, and learn your style, I dont think those books will be that much of current and up to date information. BT magazine is full of USEFUL articles, written by the real experts. Issue #1 through #4 have some of the best articles, including the best wiring howto you will ever read.