The largest section of this collection, Series I, Research Files, contains correspondence and materials gathered by MacInnis in connection with his major writing project, China Chronicles from a Lost Time: The Min River Journals. The manuscript for this work was submitted to EastBridge Books. MacInnis gathered documentation and primary sources material from the families of missionaries who had worked in the Min River valley area of Fujian (Fukien) province. According to the agreement made by MacInnis with these families, all original format primary sources that MacInnis received for his project have been transferred to the Yale Divinity School Library's China Records Project collections. The finding aid indicates which collections now contain original format materials that MacInnis received. MacInnis's research files contain extensive photocopies and letters that provide detailed information about both Protestant and Catholic missions in the Min River area.
Series II contains writings by MacInnis and by others. Series III, Personal Papers, contains family and circular letters that document MacInnis's work as a missionary in China and Taiwan, as well as his efforts in the 1990s to raise funds for flood relief in China, and biographical information. The Collected Material in Series IV includes documentation regarding Christianity in the People's Republic of China. The photographs in Series V, Audio-Visual Material, include some that were given to MacInnis by families of the Min River missionaries but they were not well-identified as to source, so have not been transferred to the Library's China Record Project collections.