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?