Acknowledged as one of the founding figures of science fiction scholarship and teaching, and one of the genre's leading writers, James Gunn in 1951 wrote what is likely the first master's thesis on modern science fiction, Modern Science Fiction: A Critical Analysis. It achieved some degree of legendary status when portions appeared in the short-lived pulp magazine Dynamic, but has otherwise remained unavailable for scholars and general readers of science fiction. Appearing for the first time in book form, this early critical work by a science fiction master is an important historical addition to the field of science fiction studies. Gunn's observations on many of the classic Golden Age stories of the 1940s, before they were classic, highlight this exuberant and astute early academic critical assessment of science fiction. Here the reader will witness the development of Gunn's critical perspective that informed his essential genre history Alternate Worlds and the monumental anthology series The Road to Science Fiction. Michael R. Page's introduction and commentary show the historical significance of Gunn's work and frame it within the context of the later development of science fiction criticism and theory.