Wladimir Köppen (1846–1940) was a German meteorologist and climatologist best known for his delineation and mapping of the climatic regions of the world. He played a major role in the advancement of climatology and meteorology for more than 70 years. Köppen’s achievements, practical and theoretical, profoundly influenced the development of atmospheric science. His greatest achievement came in 1900, when he introduced his mathematical system of climatic classification. Each of five major climate types was assigned a mathematical value according to temperature and rainfall. Since then, many of the systems introduced by other scholars have been based on Köppen’s work.