Marshall Benton Tymn is an editor and bibliographer of SF and fantasy works. He received the Pilgrim Award in 1990. He was a founder of the Instructors of Science Fiction in Higher Education.
Some of his books are A Directory of Science Fiction and Fantasy Publishing Houses and Book Dealers (1974) , A Research Guide to Science Fiction Studies: An Annotated Checklist of Primary and Secondary Sources (1977) [with L.W. Currey and Roger C. Schlobin], Index to Stories in Thematic Anthologies of Science Fiction (1978) [with L.W. Currey, Martin H. Greenberg and Joseph D. Olander], The Year's Scholarship in Science Fiction and Fantasy: 1972-1975 (1979) [with Roger C. Schlobin], A Basic Reference Shelf for Science Fiction Teachers (1978), American Fantasy and Science Fiction: Toward a Bibliography of Works Published in the United States, 1948-1973 (1979), Horror Literature: A Core Collection and Reference Guide (1981), The Science Fiction Reference Book (1981), Science Fiction, Fantasy and Weird Fiction Magazines (1985) [with Mike Ashley], and Fantasy and Horror (1999) [with Neil Barron].
For more on his career, see http://www.sf-encyclopedia.com/entry/tymn_marshall_b