Today, Dan writes about Belichick and Coughlin's time together on the staff of Bill Parcells' New York Giants. Parcells provides a few quotes, nothing very revealing. Both are serious minded and don't talk much.
If you look at it more closely, the relationship reveals itself to be less interesting. Belichick was the defensive coordinator and spent over ten years either working with or for Parcells. Coughlin was a wide receivers coach and spent three years with Parcells. I am sure much more will be made out of these three seasons in two men's 30+ year careers.