Robert P. Alexander, 80, a retired analyst with the Defense Intelligence Agency who was the author of works dealing with anthropology, linguistics and history, died of cancer Aug. 24 at Sibley Memorial Hospital. He lived in Washington.

He spent 25 years with American military intelligence before retiring from the DIA in 1970. He was a recipient of the Army's Exceptional Civilian Service Award.

Mr. Alexander was born in Japan to missionary parents. Educated in Japan and Canada, he earned his undergraduate degree at the University of Alberta. He later earned a master's degree in political science at George Washington University.

He spent 10 years in private business in Japan before returning to North America in May 1941. He spent a short time working for the British government, then served with the U.S. Custodian of Enemy Property's office and Army intelligence units during World War II.

Mr. Alexander was president emeritus and editor emeritus of the International Society for Japanese Philately, and wrote works dealing with stamp collecting. He was the author of a political history of the Ryukyu Islands and had published a comprehensive bibliography of works dealing with the anthropology of Easter Island.

He also was the author of "Kokuji," a book published by the Harvard University Press, that was a study of "Chinese" characters developed in Japan and used in the Japanese printed language. The majority of the characters used in written Japanese are borrowed from written Chinese.

Mr. Alexander's survivors include his wife of 55 years, Zoe Lemley Alexander of Washington; a daughter, Pamela Lenz of Long Island, N.Y.; a sister, Isabel Gerhard of Landover, and three grandchildren.