Gary P. Gillum is a librarian emeritus of Brigham Young University. He spent several years teaching New Testament and other courses. His main focus has been on compiling bibliographies of works in Mormon studies as well as the works of Hugh Nibley. He began his college studies at St. John's College in Winfield, Kansas, and Concordia Senior College in Fort Wayne, Indiana. He was baptized a member of The Church of Jesus Christ of Latter-day Saints in 1969. He then enrolled at BYU, where he got a master's degree in library science. Following that, he became an academic librarian at BYU, specializing in religion, philosophy, and ancient studies.

He wrote music to a poem by Arthur Henry King, which was published in a book recognizing the work of Richard L. Anderson. Brother Gillum had a long association with Anderson, since both were closely connected with the Harold B. Lee Library's Hugh Nibley Ancient Studies Room. Brother Gillum has been an editor for multiple volumes of the Collected Works of Hugh Nibley and was the compiler of Of All Things!​, a Hugh Nibley quote book.This was largely an outgrowth of having worked as Nibley's chief library aid for thirty years. Reviews by Brother Gillum have appeared in Library Journal, BYU Studies​, and several other journals. He has been a member of the Society of Biblical Literature, American Theological Library Association, and the Mormon History Association. He also served as a member of the Oxford Biblical Studies Online advisory board.