Striding toward the maitre d’ in the restaurant overlooking Parker’s Piece, the one patch of parkland left in Cambridge’s central zone, Serrin saw the first of the suits and goons arriving for the weekend seminar. Credsticks were flashing at the reception desk, and the troll chauffeurs looked stereotyped to perfection in their light gray uniforms and visors. Every bulge was in the right place, from the biceps to the licensed pistols secreted at hip and armpit.