BAllyhack has a detailed green reading book. At first it was very confusing. I also took a while to trust it. I don't use it very often but once in a while I just can't figure out which way a putt breaks or if it is uphill or downhill. Then the book is helpful. It feels like cheating. Reading greens is part of the skill of the game. Having a green reading book that is studied before play is one thing. Having it on the course is a different thing.