The charge stems from Palmer's 2002 book, An Insider's View of Mormon Origins, which challenges the traditional explanations of the faith's founding events - Joseph Smith's First Vision, the visit of the Angel Moroni, Smith's translation of ancient writings on gold plates and the restoration of the priesthood.
Palmer argues that Smith never translated anything, that the Book of Mormon reflects Smith's own 19th century milieu, not ancient America, and that Smith, considered by the faithful to be their prophet, revised the story of his visions many times to solve church disputes as they arose.
The summons is reminiscent of the 1993 sanctions imposed on six high-profile Mormon intellectuals - three men and three women - for their views on feminism, church policies and history.
Five were excommunicated and one disfellowshipped; several other people have been excommunicated or chastised in the years since.
Palmer, 64, a retired educator for The Church of Jesus Christ of Latter-day Saints in New Zealand, California and Utah, is mystified by the threat of church discipline for purportedly damaging other members' faith.
"I am very sad," Palmer said Tuesday in a phone conversation. "I love this church too much. I do not want to be excommunicated."
He realizes, though, that the book has generated controversy, especially among his former colleagues with the LDS Church Educational System (CES).
"I went to a funeral with other CES retirees recently and they talked about it a little," said Gerald Jones, who taught at the church's Institutes of Religion at the University of California Berkeley, Stanford and Yale.
"The feeling I got was that they were disappointed in him. They felt he was being disloyal and this book would hurt the church."
BYU scholars associated with the highly orthodox Foundation for Ancient Research and Mormon Studies (FARMS) issued blistering critiques, attacking Palmer's scholarship, motives and personal credentials as a church "insider."
Even more independent Mormon historians were skeptical of Palmer's reasoning.
"He presents himself as just wanting to deepen our understanding of our own history, but under his cloak, there's a dagger," said Richard Bushman, professor of history emeritus at Columbia University and author of a forthcoming biography of Joseph Smith. "Most faithful members of the church who read it will feel he's attacking their faith at its foundations."
Utah researcher Van Hale sees Palmer as open-minded and thoughtful, but one-sided in his selection of primary sources.
"He takes everybody else's statements over Joseph Smith's," said Hale, who hosts a weekly radio show, "Mormon Miscellany," and is reviewing Palmer's book for Sunstone magazine. "With that kind of bias, you are going to come up with different conclusions than most [Mormons] would."
But none of the people interviewed thought Palmer deserves to be excommunicated.
"I disagree with his bias, but I would like to think we have enough latitude in the church for someone like Grant who wants to be a member and has given a lifetime of service," Hale said. "I don't see him as doing real harm to the church."
Neither did his local Mormon leaders - until now.
Palmer said he has had several conversations about the book with his bishop and especially his stake president in the Willow Creek Sandy LDS stake, including two formal meetings last year, all of which ended amicably. He said he was never ordered to stop speaking about history or asked to disavow his conclusions.
And the book continued to be sold to LDS faithful in places like Brigham Young University bookstore in Provo.
Palmer acknowledged he may hold unorthodox views of Mormon history - in 1988, he had grown so uncomfortable with some of what he was expected to teach that he volunteered to work for the church counseling at the Salt Lake County Jail. He said he remains deeply committed to the practice of Mormonism, paying tithing, attending church, heeding the Word of Wisdom and, he said, bearing "a strong testimony of Jesus Christ."
LDS Church spokesman Dale Bills declined to comment, saying only, "The church considers disciplinary matters to be confidential." Willow Creek Stake President Keith Adams, who issued the summons in a letter dated Nov. 28, did not return phone calls.