David F. Long, 83, of 81 Mill Road, Durham, NH died on January 14, 2001 at the Inn at Deerfield after a lengthy illness. Mr. Long was born on December 8, 1917 in Cleveland, Ohio, the son of the late Roger and Christine (Foster) Long. He graduated from Dartmouth College in 1939 where he received his AB and from Columbia University in NY where he received his Ph.D.. In 1948 he became a member of the history department at the University of New Hampshire where he remained for 45 years specializing in American History and History of Foreign Relations. He was also an author of several naval history biographies and books on US Foreign Policy. He was a fulbright lecturer at Sri Lanka, New Zealand, Australia, Uganda, Hong Kong and Korea and was a visiting professor of history on the Semester at Sea Program. He was an enrichment lecturer on cruise ships in history and current events worldwide. He received ''A Profile of Service Award'' from the University of New Hampshire Alumni Association and in 1993 he received the American Naval Biography Book Award from the Society for Oceanic History for his writing of Mad Jack: The Biography of Captain John Percival, USN. Family members include; his wife of 32 years, Susan (Robinson) Long; two sons, Craig Long of Bremerton, WA and Roger Long of Grapevine, Texas; one daughter, Elisabeth Lilly of Culver City, CA; and two granddaughters.