At 9 p.m. last night, Bank Street was humming with black Mercedeses, all idling for the air conditioning. "It's gotta be cold when my client comes out," said one driver. A bright red motorcycle with Diplomat plates screeched to a halt and an olive-skinned man bounded off into the most literarily significant inn since the Tabard. As prescribed by the Post's Mandy Stadtmiller, we had made reservations through Jon Kelly, Graydon Carter's assistant.