What is Coding System

This chapter outlines the history of medical classifications in a general cultural context. Classification is a general phenomenon in science and has an outstanding role in the biomedical sciences. Its general principles started to be developed in ancient times, while domain classifications, particularly medical classifications have been constructed from about the 16th-17th century. We demonstrate with several examples that all classifications reflect an underlying theory. The development of the notion of disease during the 17th-19th century essentially influenced disease classifications. Development of classifications currently used in computerised information systems started before the computer era, but computational aspects reshape essentially the whole picture. A new generation of classifications is expected in biomedicine that depends less on human classification effort but uses the power of automated classifiers and reasoners.