I'm very proud of Zeus. He's doing fabulously well, but I have a few questions. He's now about 15 months old, and he's really starting to settle down. I normally do training sessions in a few short 15-minute sessions throughout the day, but that doesn't seem long enough to work on the more complicated stuff. I'd like to start working with him for a 1-hour block daily. Now that he's older, I think his attention span can handle it. But is this too long? Almost all the obedience books I read recommend very short sessions. Also, can someone recommend a good book on dog training? Not basic stuff, but advanced obedience. I'd like to start Zeus on some utility dog training and tracking, and I'd feel more comfortable with a guide of some kind.