Not so much an "International Man of Mystery" as a "North East Kingdom Man of Mystery".  Mark is silent but deadly, not in the smelly fart kind of way, but in how you don't realize he's riding behind you until you bobble on the technical section of trail and then he passes you . . . silently . . . with the only sound being your ego crashing to the dirt.  He is an avid NPR listener and has pin-up posters of Diane Reams in his cubicle.