I've gotten a lot from this book.  First, it's not a prescription for treatment, which seems to be your focus now, but gives options and explains them.  There's lots of approaches and it's good to see the array.  It gave me a good basis for making decisions.  It was invaluable in managing Fallon's diet change.  It was written by 2 prominent experts in the field.  It's a better resource than the conflicting, unvetted (no pun intended) information you can find on the internet.  

But how you spend your money is up to you.  Good luck!!