Peony is set in the 1850s in the city of K'aifeng, in the province of Honan, which was historically a center for Chinese Jews. The novel follows Peony, a Chinese bondmaid of the prominent Jewish family of Ezra ben Israel, and shows through her eyes how the Jewish community was regarded in K'aifeng at a time when most of the Jews had come to think of themselves as Chinese. The novel contains a hidden love and shows the importance of duty along with the challenges of life. This novel is one that follows the guidelines of Buck's work. The setting is China, religion is involved, and there is an interracial couple (David and Kueilan).
A prefatory note before the title page tells the reader of the assimilation of the Jews of K'aifeng. "Today even the memory of their origin is gone. They are Chinese."
Not all the 1st editions have the same cover design; some have a light blue binding with the title centered in a 3"x 1.5" simple gold imprint on dark blue background, the sun shining on a field, with the title at the top and the author's name at the bottom. Much more is known today (2010) than in Buck's lifetime about the K'aifeng Jews.