Dr. Gordon W. Prange, 69, a history professor at the University of Maryland who was the author of "Tora! Tora! Tora!," an account of the Japanese attack on Pearl Harbor, died of cancer Thursday at the University of Maryland Hospital in Baltimore.

Dr. Prange was an authority on the Pacific campaigns of World War II, the military occupation of Japan, and the career of Gen. of the Army Douglas MacArthur.

From 1946 to 1951, he served on Gen. MacArthur's general staff in Tokyo.

During these years he directed an Army historical staff of more than 80 persons, including former Japanese military officers as well as U.S. Army officers and enlisted men, to produce a history on the operations of Gen. MacArthur.

The work resulted in the "Reports of General MacArthur." It was not published until after MacArthur's death in 1964, in accordance with the general's wishes.

In addition to "Tora! Tora! Tora!," which was made into a movie by 20th Century Fox in 1966, he also was the author of several other popular works. These included "Master Spy," the story of Soviet intelligence agent Dr. Richard Sorge, and "Miracle at Midway," the story of the naval battle which turned the tide against the Japanese in World War II.

Dr. Prange was a native of Pomeroy, Iowa, and earned both bachelor's and doctoral degrees at the University of Iowa. He joined the faculty at the University of Maryland in 1937, leaving in 1942 to enlist in the Navy.

During the war he graduated from the Navy's military government school at Columbia University and then taught in a military government program at Princeton University. He went to Japan with the American Occupation Forces. He stayed on as a civilian.

He returned to the University of Maryland in 1951 and brought some 450 crates of books, newspapers and periodicals with him concerning the military occupation of Japan.

The materials were accepted by the University of Maryland's McKeldin Library and designated the Gordon W. Prange Collection. They formed the basis of much of his subsequent work.

During his years at the university, he received a number of awards, including a 1962 citation from the Men's League as the "Outstanding Faculty Member." In 1979 and 1980, he received Student Government Association Outstanding Teacher Awards. He taught at the university until the time of his death and lived in University Park.

Survivors include his wife, Anne Root Prange, and a daughter, Polly, both of University Park; another daughter, Nancy P. Helms of Beltsville; a son, Winfred T. R. Prange of Howard County, a brother, Russell, of Pomeroy, and one grandchild.

The family suggests that expressions of sympathy be in the form of contributions to the University of Maryland McKeldin Library for the Gordon W. Prange Collection.