The Patricia Koo Tsien and Kia Chi Tsien papers document the decades of internationally rooted lives of the Tsien couple, as well as family history materials on the Koo and Tsien families. The bulk of the papers consist of files associated with the professional and personal trajectories of Patricia Koo Tsien and Kia Chi Tsien, arranged in respective series. Also included are materials pertaining to the research of Koo and Tsien's family histories, in particular manuscripts, transcripts, and annotated copies of the Wellington Koo Memoir, and materials on Oei Huilan, Madame Wellington Koo.