Spencer W. Kimball, 90, the president and prophet of the Mormon Church since 1973 and one of its most energetic leaders until age and infirmity curtailed his ministry, died Nov. 5 at his home here.

He had undergone operations for throat cancer and heart ailments and on three other occasions to remove subdural hematomas -- scar tissue and blood between his brain and skull.

Mr. Kimball, the 12th "prophet, seer and revelator" of the 5.8 million-member Church of Jesus Christ of Latter-day Saints, administered the most significant changes since pioneer days in the largest and wealthiest church founded in America.

As president, he allowed blacks to enter the Mormon priesthood, stunned the Pentagon by opposing the installation of MX missiles in Utah, retired elderly church leaders, added the first non-Americans to the modern church hierarchy, and consolidated all Sunday church meetings into a three-hour block. His staunch opposition to the proposed Equal Rights Amendment angered women's rights activists.

On learning of Mr. Kimball's death, Sen. Jake Garn (R-Utah) said, "It's a great loss to millions of people around the world and a very personal loss for my wife and me." Mr. Kimball had officiated at the Garns' marriage.

Church presidents serve for life and are the product of an apostolic succession within the Council of the Twelve. If tradition holds, that body's president and most senior member, former secretary of Agriculture Ezra Taft Benson, 86, will succeed Mr. Kimball once a pro-forma vote of the Twelve is taken.

Mr. Kimball strongly opposed construction of the MX missile system in Utah and Nevada, and a May 1981, statement to that effect dealt a heavy blow to a basing system that would have spread the missiles across the two states.

On June 9, 1978, the three-member First Presidency of the church announced a change in doctrine to allow ordination of blacks of African descent to the church's all-male priesthood. The First Presidency said the change came in a revelation from God to Mr. Kimball. This was the first major revelation announced by a Mormon prophet since Wilford Woodruff issued a manifesto in 1890 ending the practice of polygamy.

Every faithful Mormon male over age 11 holds one of several priesthood offices. The 148-year-old ban on blacks in the priesthood, which engendered lawsuits and internal dissent, had prevented blacks from performing routine ordinances affecting their own families and from attending church temples or attaining leadership positions.

Mr. Kimball became president of the church on Dec. 31, 1973, following the death of president Harold B. Lee. During his tenure, church membership nearly doubled. Its full-time missionary force also nearly doubled from 16,000 and Mr. Kimball announced plans for dozens of new temples.

More than any of his predecessors, he carried his gospel message personally to the world. He traveled thousands of miles to church conferences, stressing the need for an energetic battle against wrongdoing and preaching acceptance of Jesus Christ through repentance and baptism in the Mormon Church.

The three-fold goal of the church in modern times, he proclaimed in April 1980, is to preach the gospel to all, to help Mormons eventually achieve godhood, and to perform temple rites for everyone who ever lived, reflecting the Mormon belief that the Mormon faith can be embraced in the afterlife.

During his tenure as "prophet, seer and revelator," Mr. Kimball also emphasized the family as the cornerstone of society and led the church on a crusade against pornography.

Spencer Wooley Kimball was born on March 28, 1895, in Salt Lake City, the sixth of 11 children of a 19th century Mormon missionary assigned to Oklahoma Indian Territory and to the Gila Valley of Arizona. His grandfather, Heber C. Kimball, was one of the original "Twelve Apostles" appointed by Joseph Smith Jr., founder of the church, in 1830.

Mr. Kimball was a banker, a real estate and insurance salesman and a radio station operator before joining the church's full-time leaders as a member of the Council of the Twelve in 1943.

As a church official, he devoted much of his time to Indian programs, helping found a placement service in which Indian students lived with Mormon families while attending school. He headed the church's Indian programs for a quarter of a century.

Before becoming church president, Mr. Kimball served 30 years as a member of the Twelve, traveling to nearly every country where there are Mormon missions and congregations. As president, his itinerary expanded to include East Germany, Poland and Yugoslavia -- the first time a church president had visited communist nations.

Survivors include his wife, the former Camilla Eyring; three sons, and one daughter.