Which author is recognized for introducing the modern short story with works like "The Secret Life of Walter Mitty"?

The recognition of James Thurber for introducing the modern short story primarily stems from his unique storytelling style and innovative use of humor, particularly seen in works like "The Secret Life of Walter Mitty." This story exemplifies the characteristics of modern short fiction by focusing on the inner life of its protagonist, portraying the contrast between the mundane reality and the rich fantasy life of Walter Mitty. Thurber's ability to blend humor with poignant social commentary also adds depth to his narratives, setting a benchmark for future short stories. His contributions are significant in shaping the form and direction of the modern short story genre.