The Capital Library of China houses more than 6.5 million books of all kinds, covering both ancient and contemporary as well as Chinese and foreign books. The collections are in all disciplines and types, including rare ancient books, Beijing local literature, contemporary books and newspapers, audiovisual materials and foreign books and journals. There are about 500,000 ancient books with 6,000 rare ones, with the Chewangfu Music Book containing 1,600 written works on traditional opera and Chinese folk art songs, which are a treasure repertoire for doing research on Chinese folk art, folk conditions and folk customs. There are about 50,000 kinds of local literature with the total number of 160,000 volumes, which cover all the Beijing local literature that can be found and can be considered as the literature resources system for research. There are more than 20,000 old disks covering traditional opera, Chinese folk art songs and music with precious ones on Peking opera, cross talk and pop songs, with the old disk the Five-flower Hole in Four Pairs, the only disk performed by the Four Huadan (Mei Lanfang, Cheng Yanqiu, Shang Xiaoyun, and Gou Huisheng).