Edit: just to elaborate on this. I hear often from people "what math do i need to learn so i can do X?" And I just think that alot of the time people should just do X and this will force them to figure out the math as needed. Learning math from a book is brutally difficult! Just like learning a programming language, what is the best way to do that? You start with a project that you want to do. People who want to read the "pre-requisite book" often-times just seem to be deferring the real crunch that happens when you actually get down to the business of actually learning X.