From the beginning of his 10-year tenure as LDS Church historian, Leonard J. Arrington’s quest for the unvarnished truth about Mormonism’s past spurred the relentless, sometimes crippling ire of his faith’s most conservative leaders — from apostle Boyd K. Packer to eventual church President Ezra Taft Benson.

“The church suffers from the boomerang effect of criticism,” Arrington wrote in his journal July 17, 1972. “It will not allow criticism within the church, so it is abnormally sensitive to criticism that comes from without the church.”

That lament, among many shared publicly for the first time in Signature Books’ new “Confessions of a Mormon Historian: The Diaries of Leonard J. Arrington,” came just seven months after he was named to the post in 1972.

Nonetheless, the “Arrington Spring” — as his gathering of talented researchers and writers and their subsequent flood of articles and books came to be known — persisted. Within a few years, though, it had been largely driven out of church-approved venues to alternative and secular outlets by a small but resolute cadre of apostles and retrenchment allies.

To these men, including Benson, Packer and then-apostle Mark E. Petersen, Arrington’s scholarly approach, along with the opening up of The Church of Jesus Christ of Latter-day Saints’ long-restricted document archives, was just too freewheeling — to the point of sacrificing official church history’s primary “faith-promoting” role on the altar of academic candor and inquiry. ...