One of the foremost Czech paleontologists, researcher of global impor- tance, Oldřich Fejfar, celebrated his ninetieth birthday on January 8, 2021. His research in the Bohemian Karst was initiated by the discovery of the Koněprusy Caves in 1950.
In the following years (especially in 1955-1957) he performed a detailed research of a sediment-fi lled karst depression C 718 located in a quarry adjacent to the Caves. Here, he de- veloped techniques for a detailed study and quantitative analysis of ver- tebrate microfauna based on processing of large sediment samples.
Later, he worked at many other localities of the area, concentrating on both vertebrate macrofauna and microfauna. Following the pioneering works of Miklós Kretzoi and in cooperation with W.
D. Heinrich, he devel- oped a general biostratigraphic system of the European younger Cenozoic, which serves as a basis for interpretations until these days.
He performed his studies in numerous European and non-European countries. Equally important are his educational and science-promotion activities.