Warren H. Reynolds, a State Department historian for 30 years, died Jan. 19 at Suburban Hospital in Bethesda. He was 90 and lived in Washington.

The cause was complications from pneumonia, said his son Stephen L. Reynolds.

Dr. Reynolds retired from the State Department in 1986. As a historian, he specialized in foreign affairs, including the United States and Vietnam, and international treaties related to Antarctica, including the establishment of facilities there for scientific purposes.

Warren Harding Reynolds was born in Poughkeepsie, N.Y. He served in the Army during World War II and participated in combat operations in France and Germany....