There are some books (Erudite's Picatrix of Casting) that you can buy on the market board which is relatively cheap; around 30K+ gil or so. The easy part is getting the book. The really hard part is getting someone to actually meld the material into the book for you. I have been at this for two weeks now and have yet to find anyone who will meld the material in to the book for me. I even offered to pay 10K gil for it but no luck.