The act of writing about writing should carry with it a bright flashing neon warning sign that reads “Danger: Potential Self-Absorption Ahead.” Authors are intrinsically more interested in the subject than their readers, and only the best can get away with it without being self-indulgent. But Tom Grimes’ memoir Mentor—about his early career as a novelist (Season’s End) and his relationship with his mentor, Frank Conroy—is refreshingly genuine and engaging. His memories are steeped in the writerly process, but the book also encompasses more universal themes: expectation, disappointment, and the need to impress your heroes. What Grimes does, beautifully, is emphasize the communal elements of a solitary profession. A?