Zhang Nan, courtesy name Xugu, was a renowned physician during the Qing Dynasty, spanning the Jiaqing to Daoguang eras. He hailed from Daoxu, Kuaiji (now part of Shangyu). Frail and often ill in his youth, as an adult he led a reclusive life, indifferent to fame, dedicating himself solely to the study of medicine. He did not follow the Shichuan school, thus his learning was not confined to a single doctrine. He greatly admired the "Medical Cases of Ye Tianshi," stating, "Ye's scholarship, synthesizing a hundred schools and integrating the principles of meridian tropism, is like adding the finishing touch to a painting of a dragon, creating a distinct school of its own." Consequently, Zhang traveled to Wumen, where he consulted with numerous physicians and developed his own theories, particularly making significant contributions to the theory of warm diseases. His works include "Yimen Banghe" (published in the ninth year of Daoguang, 1829), "Yimen Banghe, Second Collection" (published in the fifteenth year of Shouguang, 1835), and "Classified Compilation of Annotations on Suwen" (unpublished).