A pull-hook is an outside-in swing witht the face closed to the swing path.

IMHO there are 2 main causes:

1. Double-Cross. - While hitting an intentional fade you close the face. This gives a powerful pull or pull-hook.

2. Over-the-Top - This dreaded malady affects us all at some point. It seems that most swing errors at the top of the swing or early downswing push the hands out of the swing plane and releases the wrists early. The result is often a weak pull-hook. There are as many cures as there are swing faults.

For me the best cure is a straighter left arm and a longer, more relaxed pause at the top. Perhaps getting less ambitious and shortening my backswing would also help.

Doug