Hal Clement (pseudonym for Harry C. Stubbs, 1922-2003) is often called “the dean of hard sf.”  He earned a B.S. in astronomy from Harvard, a MS in chemistry from Simmons College and taught high school science for forty years.  He ran 35 combat missions with the 8th Air Force Division in World War II and retired as full colonel in 1976.  His story “Proof” appeared in Astounding Science Fiction in 1942, to be followed by many stories and novels, including MISSION OF GRAVITY, ICEWORLD, CLOSE TO CRITICAL, STAR LIGHT and STILL RIVER.   The author was a frequent and well-loved attendee and lecturer at science fiction conventions.  He received SFWA’s Grand Master Award in 1998.