For ages Chernozems were recognized as the most fertile soils in Eurasia; the scientific study of soils started from Chernozems. However, the concept of the genesis of Chernozems evolved since the 19th century. This evolution was somewhat circular because many researchers returned back to the theories that stressed the importance of excessive moisture in the past and specific paleoclimates in the formation of Chernozems rather than the contribution of current vegetative cover. The study of Chernozems and Chernozem-like soils throughout the world resulted in the amplification of the concept of the genesis of these soils. In places, we observe the convergence of soils of different genesis that leads to the formation of similar deep black soil horizons. Soil classifications reflect the diversity of Chernozem-like soils; some classifications are inclusive, and the others intend to divide black soils into several distinct groups. Taxonomic distance analysis shows that most Chernozems and Chernozem-like soils form a compact group, though dark-coloured Rendzinas and Vertisol-like soils show high dissimilarity with Chernozems.