If you ask members of The Church of Jesus Christ of Latter-day Saints if they know about the “Three Nephites,” chances are most will know the allusion. The story comes from the Book of Mormon in chapters where the risen Christ visits the Americas and chooses 12 apostles. Of those, three ask to linger in mortality until Jesus comes again, ministering to the people. From the time when the book of scripture was first published until today, members have reported encounters with these shape-shifting strangers, who seem to pop up randomly angelic visitors of sorts sent to help people. For decades, Brigham Young University professor William A. “Bert” Wilson, seen as “the father of Mormon folklore,” gathered these accounts. After he died in 2016, the collection went to one of his students, Julie Swallow, a teaching and learning consultant at the church-owned Provo school. The collection now forms the nucleus of a new book, “The Three Nephites: Saints, Service, and Supernatural Legend,” from Swallow and co-authors Christopher Blythe, Eric Eliason and Jill Terry Rudy. On this week’s show, Swallow and Blythe, an assistant professor of folklore at BYU and co-host of the “Angels and Seerstones” podcast, discuss these stories, what they mean spiritually and communally, and why the “Three Nephites” continue to engage and entertain believers.