Abstract: Having worked together with Dr. Pei Wenzhong (W. C. Pei) for a very long time, I know clearly how he conducted himself. We had only separated for about two years after the Pearl Harbor incident when we left temporarily the Cenozoic Research Laboratory but still wrote to each other regularly. Frequent correspondence was also kept between us even when he studied in France, and so I had probably preserved with me the largest number of his letters.Having graduated from the Geology Department of Peking University in 1927,Dr. Pei participated the Geological Survey of China. He recalled that as the quota of the Geological Survey has then been filled, Dr. Wong Wenhao (W. H. Wong), the director of the Geological Survey, ordered Pei to work temporarily in the charting Section with a meager salary. In 1928, when the Chinese geologist Li Jie (C. Lee) and the Swedish mammal paleontologist B. Bohlin left Zhoukoudian,where an excavation work under the guidance of the Cenozoic Research Laboratory was being conducted, Yang Zhongjian (C. C. Young) and Pei were appointed by Wong Wenhao to take over the work.Dr. Pei's hardworking spirit is really admirable. When I participated the work in Zhoukoudian in 1931, I found that he was busy at work from morning till night with almost no leisure at all; he had neither "Sunday" nor holiday, and he read all the time beside working. His such attitude toward work affected me very much. One of the largest merits of his is the spirit of bearing hardships and willingness to work hard. When I accompanied him to do survey in the Hexi Corridor, he Searched around. in the Gobi no matter how hard was the going and climbed any mountain no matter how difficult to climb, whenever it was necessary. In the field, he was easygoing about food and drink. So far as I know, he had no hobby of any kind beyond the work of his own job. He worked half a year annually in Zhoukoudian, but in his dwelling place there was not even a radio.The field work is considered by somebody to be very easy, but this is in fact not the case. Taking the work in Zhoukoudian as an example, it was stipulated that "today's work must be done today". Being the person in charge of the excavation work, Dr. Pei Wenzbong had to go here and there everyday throughout all the excavation sites no matter how many sites there were, to examine the findings from each site. Any important specimen found should be picked out immediately and registered into the Daily Report, otherwise there should be an omission. This requirement was very profitable to all working personnel in keeping the high quality of work. Thereafter, as Dr. Pei Wenzhong was too busy, this work was taken over by Bian Meinian (Dr. M. N. Bien) and me, who kaye learned much from him. Another example may illustrate Dr. Pei's hardworking attitude. Being a geologist,he was quite inexperienced in management of general affairs and excavation work when he took part in the work in Zhoukoudian in 1928, and he even could not distinguish deer teeth from horse teeth and dog teeth in the beginning, but he never hesitated to ask for advice from skilled workers on fossil identification. However,because of his unremitting efforts, he soon became an expert. He was very interested in the carnivores found from the Peking Man site in Zhoukoudian. Since 1931,when I participated work, he began to pay attention to carnivore fossils and examined the details of various species. Through his study, the carnivores were classified into five families and 28 species at that time, and a monograph with the title of "On the Carnivora from Locality I of Choukoutien" with 166 pages .and 26 plates was published in 1934 (Palaeontologica Sinica, Series C, No. 8).At that time Dr. Yang Zhongjian and Dr. Pei Wenzhong took different, rcsponsibilities of their own. Dr. Yang's study field extended to older history and animals, and he dealt at last with dinosaurs; whereas Dr. Pei's study field covered the younger history and animals and dealt specially with Quaternary mammal fossilsWith a wide scope of knowledge, Dr. Pei also to