This is the diary of Horace P. Stimson, the young doctor on the Fogg Museum's second expedition to Tunhuang and other cave temples in western China in 1925. The expedition was led by Langdon Warner and included: Horace Jayne, Alan Priest, Richard Starr, and Daniel Thompson from the United States, as well as the Ch'en Wan-Li from Peking National University and Wang Chin-jen, the interpreter. The purpose of the expedition was to survey, photograph, and potentially acquire Buddhist cave paintings for the museum's collection, but this goal was thwarted at the principal site, Tunhuang, by the local people who were offended by Warner's actions at the caves on his first expedition the year before. Despite their limited success at Tunhuang, the members of the expedition enjoyed interacting with American expatriates in Peking, traveling westward in mule carts through Shansi and Shensi provinces and the Kansu corridor, and exploring and photographing other caves on their return to Peking.

As a doctor, Stimson was a close observer of his fellow expeditioners, candidly describing their personality traits as well as their health problems. As a young man who had never before traveled outside the United States, he also recorded his impressions of the foreigners and Chinese people he encountered, the missionaries and the officials who wined and dined the Americans as well as the peasants who came to him for treatment.

His diary also includes many drawings and photographs of people and places.