LETTER from TERRY BERKSON ‘It’s The Knuckle On Your Middle Finger That Does It’ About 15 years ago, after having read several of his books, I heard that Jim Harrison, the writer and poet, was giving a reading and a talk at Barnes & Noble on Union Square in Manhattan. Several months before at a barbeque on Canadarago Lake outside of Richfield Springs, I had talked at length about Harrison’s “Legends of the Fall,” and several of his other works,…