In 2011, the photographer Tanyth Berkeley went to Colorado City, Arizona, to meet a woman named Ruth, a member of the Fundamentalist Church of Jesus Christ of Latter-day Saints, a polygamist sect of Mormonism. As we learn in Berkeley's new photo book, “The Walking Woman,” Ruth had grown up and married within a branch of the community in Arizona, in which women were instructed to “keep sweet” and submissive, and children, including her many siblings, were beaten into silence. But she had spoken out against the abuse in a documentary film “Banking on Heaven,” from 2005, and appealed to the F.L.D.S. church and local authorities for justice. Instead, she was declared “mentally unfit and institutionalized,” according to the film, and then “exiled from her home and not allowed to see her children.” Berkeley wanted to “see this rebel for myself . . . to congratulate her on her courage and to give her support.”