Petar Beron, Sc.D. worked at the Institute of Zoology and the National Museum of Natural History at the Bulgarian Academy of Sciences as a biologist from 1963 to 2010. Specializing in acarology and biospeleology,  he began exploring caves and cave fauna since 1955. He went on expeditions in New Guinea, Indonesia, Mexico, Cuba, China, Vietnam, on the Balkan Peninsula, in Corsica and South America. In his journeys, he discovered many new species of caves and animals. Author and co-author of many books and articles on speleology, zoogeography and acarology.

The present publication contains data on 153 species not recorded so far in the previous catalogues of Bulgarian cave fauna. Data on 813 caves, including 189 published for the first time in the list of caves from which animals have been recorded find place. After these changes the total number of the animals known from Bulgarian caves becomes 866 (including 130 troglobite and 72 stygobite species). The updated bibliography of Bulgarian cave fauna contains 584 titles.