Originally Posted by: shahnenhey i already have i basic understanding of music theory (i read the complete idiots guide to music theory:second edition) is it worth it to go more advanced and get the book harmony by waltor piston? i play rock and roll and i wanna b the best i can possibly be. thanks

A good idea might be also to get a good teacher (if you haven't one) and let him decide what really is important for your playing skills at the moment. Do not waste your time on theory stuff that does not matter for where you are NOW at the moment.