From 1981 until 1986, the archaeologist Judith McKenzie, then a graduate student at the University of Sydney, traveled to the ancient site of Petra in Jordan, living in a cave there for extended periods, in order to survey and measure architectural moldings on the rock-cut monuments. It was a critical time in the history of Petra, where, for centuries, its local inhabitants, known as the Bdoul, had lived and worked. But that tradition was coming to...