In the early 20th century, the passionatt fiction editor at McClure’s magazine mentored Willa Cather and O. Henry, took long walks through Manhattan in place of staying put at a desk, read and smoked cigarettes on park benches in all kinds of weather. She was, as this author writes, “a talent whisperer and literary booster,” and even though she was one of the world’s great conversationalists, she left no autobiography.