Jermaine Griggs's resources have helped me tremendously. I have been playing keys since 1993, but didn't really understand the concept of theory, progressions, and all my keys until I heard of Hearandplay.com. I purchased his thick course, the 300 pg workbook. I got through with it within 3 months. Since purchasing the book, I am currently playing for three different churches. One church as the main director, and two as a keyboardist. I don't really have a favorite key anymore. It used to be Bb, until I heard of Hearandplay.com. I play all styles now, not just gospel. So if you are serious, and serious only, then this is the site to invest in your playing. Thanks & be blessed!