The Nathaniel Baldwin Diaries (1897-1961) are photocopies of a microfilm copy of original journals written by Baldwin, a Salt Lake City religious leader and inventor. The son of converts to the Church of Jesus Christ of Latter-day Saints (LDS), Baldwin was born in Fillmore, Utah, in 1878. He attended Brigham Young Academy and Utah State Agricultural College. He completed his education in physics and electrical engineering at Stanford University. Soon after, while teaching physics and theology at Brigham Young University (BYU), Baldwin became involved in the Mormon Fundamentalist movement. A primary tenet of the Fundamentalist movement was support of polygamy and Baldwin was fired from BYU due to his stand on this issue. To produce a widely-used amplification device that utilized compressed air, Baldwin built a factory on the east side of the Salt Lake Valley. The business became successful and Baldwin reputedly used the profits to support other Fundamentalists. In 1930, fraudulent business practices led to an imprisonment that lasted until 1932. The remainder of his life was impoverished and he died in 1961 in Salt Lake City. In addition to recording Baldwin's personal experiences, the journals also contain financial records stemming from Baldwin's involvement with various LDS congregations, particularly the East Millcreek Ward of the LDS church. An inventory is available.