Carved into the mountains of northern China, the Buddhist cave temples of Xiangtangshan were the crowning cultural achievement of the sixth-century Northern Qi dynasty. Once home to a magnificent array of limestone sculptures, the caves were heavily damaged during the first half of the twentieth century, and much of the work housed there was lost to the international art market. The exhibition Echoes of the Past - co-organized by the University of Chicago's Smart Museum of Art and the Smithsonian Institution's Arthur M. Sackler Gallery - draws upon the findings of a multiyear research project headed by Katherine R. Tsiang at the University of Chicago's Center for the Arts of East Asia. Using such twenty-first-century technologies as 3-D scanning, Tsiang and an international team of technicians and scholars have identified many of the dispersed sculptures from Xiangtangshan in an effort to shed new light on the original beauty and meaning of the cave temples. This exhibition catalog features entries with full-color illustrations of the works in the exhibition, as well as six new essays discussing the artistic, historical, and religious significance of the caves and their sculptures and recent research dedicated to their digital reconstruction.