Samuel P. Huntington, a resident of Boston and longtime summer resident of West Tisbury, died Dec. 24 at Windemere Nursing and Rehabilitation Facility in Oak Bluffs after a long illness. He was 81.

He was the Albert J. Weatherhead 3rd University Professor at Harvard, where he taught for 58 years before his retirement in 2007. A gifted teacher, scholar and mentor to a generation of scholars in widely divergent fields, he was the author or co-author of 17 books, on American government, democratization, national security and strategic issues, political and economic development, cultural factors in world politics and American national identity. His most widely-known book, The Clash of Civilizations, was published in 1997 and is in print in 39 languages. His first book, The Soldier and the State, published in 1957 and now in its 15th printing and in use at all the service academies, was the subject of a West Point symposium last year on its 50th anniversary. Political Order in Changing Societies, published in 1969, is widely regarded as a landmark analysis of political and economic development in the Third World.

A graduate of Stuyvesant High School in New York city, he entered Yale University at the age of 16 and graduated in two and one-half years in the Class of 1946. He then served in the U.S. Army, earned a master’s degree in political science from the University of Chicago and a Ph. D. from Harvard in 1949.

At Harvard, he served two terms as chairman of the government department and for 12 years as director of the Center for International Affairs. He was the founding director of the Olin Institute for Strategic Studies and the chairman of the Harvard Academy for International and Area Studies. He was president of the American Political Science Association and received the Grawemeyer Award for Ideas for Improving World Order.

A life-long Democrat, Professor Huntington was foreign policy advisor to Vice President Hubert Humphrey in the 1968 presidential campaign and served in the Carter White House on the National Security Council staff as Coordinator of Security Planning. In the wake of the bitter 1968 campaign, he and Warren Manshel, political opponents in the campaign but close friends, co-founded and edited Foreign Policy magazine, which was dedicated to developing a new foreign policy consensus.

A summer resident of West Tisbury since 1966, Professor Huntington and his wife, Nancy, first came to the Vineyard on their honeymoon in 1957. He was a familiar figure on his morning jog around the outskirts of West Tisbury village and, upon returning home, would report on his meetings with the other regular walkers and joggers. He was always able to work very productively and happily in his study in his barn, but he was also always able to step out of his study, play tennis, sail his Sunfish on Tisbury Great Pond, take an afternoon swim at Lambert’ Cove, walk at Quansoo, or, his favorite activity, simply rake leaves and putter about the garden.

Devoted to his family, he is survived by his wife of 51 years, Nancy Arkelyan Huntington, two sons, Timothy Mayo Huntington and Nicholas Phillips Huntington, two daughters in law, Kelly Brown Huntington and Noelle Lalley Huntington, and four greatly beloved grandchildren, Candace, Max, Eliza and Anna. A private family burial service was held at the West Tisbury cemetery on Tuesday, Dec. 30.