Thanks to the abundance of old documents as wel as the excellent descriptive work conducted both by the Chinese themselves and foreigners, the study of Chinese phonology has flourished. This paper, which consists of the following seven sections, introduces various approaches taken in past studies of Chinese phonology, discusses current theoretical issues, and points out some of the important topics in this area. (1) The concept of ‘layer’ in historical phonology (2) Studies on the compiling process for documents on Chinese historical phonology (3) A method of projecting family trees on geographical distribution (4) Tracing recent phonological changes (5) Historical studies on tone and stress accent (6) Bilingual documents (7) Studies on old Chinese phonology and genetic relation between Chinese and the other language families
