Lawrence R. Flake, Prophets and Apostles of the Last Dispensation (Provo, UT: Religious Studies Center, Brigham Young University, 2001), 473–74.
Born: 10 June 1877, Salt Lake City, Utah
Presiding bishop of the Church: 4 June 1925
Associate to the Quorum of the Twelve Apostles: 6 April 1938 to 6 October 1939
Ordained an apostle (not in the Quorum of the Twelve): 14 April 1938 (age 60)
Quorum of the Twelve Apostles: 6 October 1939 (age 62)
Died: 29 May 1943 (age 65), Salt Lake City, Utah
The youngest of eleven children born to President George Q. Cannon and his first wife, Elizabeth Hoagland, Sylvester Quayle Cannon was reared in the secure and sheltered atmosphere of the family farm, where the wives and children of President Cannon all lived together. He attended the private school that was maintained there for the Cannon children and ate his meals with the large family in the communal dining hall. The boy had every opportunity for a fine education, and having qualified himself in stenography at LDS College, Sylvester traveled as his father’s personal secretary on an extensive tour of the eastern states and England.
Following further study at the University of Utah, he attended for four years the distinguished Massachusetts Institute of Technology, obtaining a master of science degree in mining engineering and metallurgy. Shortly after completing this degree, he was called to the Netherlands and Belgian Mission, where his knowledge of German and French was of great value. In 1900, about one year after arriving in this field, he was called to serve as president of the mission. Seven years later he returned to the Netherlands as mission president again, this time in the company of his wife, Winnifred Seville, and their two little daughters. Having previously supervised the translation of the Doctrine and Covenants into Dutch, he published it for the first time in that language during this mission.
Putting his education to good use in behalf of the state of Utah, Brother Cannon was hired to make a survey of irrigated lands and water from the Weber River. He became a member of the Utah Society of Civil Engineering, chair of the governor’s State Flood Commission, a member of the State Advisory Council for Unemployment, and supervisor of all engineering projects for Salt Lake City.
His greatest callings were those given to him in the Church. After serving as president of the Pioneer Stake for eight years, he was called to succeed Charles W. Nibley as the presiding bishop of the Church. In 1938 he became an apostle and served faithfully in that calling until his death in 1943.
At the time of Elder Cannon’s passing, President David O. McKay addressed the funeral congregation with these words: “The hardest battles of life are fought within the chambers of the soul . . . . Brother Cannon was master of himself because he fought victoriously those inner battles.” 
 David O. McKay, “Sylvester Q. Cannon,” Improvement Era, August 1943, 465, also 509–10; see also “Bishop Sylvester Q. Cannon,” Improvement Era, July 1925, 886–88.