Ajdovska jama near Krsko in Slovenia is a small passage cave that arouses great scientific interest for several reasons. A number of archaeological excavations have shown that the cave contains both Upper Pleistocene and early Holocene sediments, as well as Palaeolithic finds and faunal remains. During the first excavations carried out by Srecko Brodar in 1938, significant Upper Pleistocene finds were made. These were given to the museum in Celje, but were destroyed during World War II. An excavation in 1967 showed that Ajdovska jama was also a Neolithic necropolis of great importance. Later excavations mainly focused on Neolithic layers at the back of the cave. This led to sensational results. Undisturbed layers containing cave bear bones were also found, thus dating these layers to the Pleistocene. A short excavation was undertaken in 2001 by the University of Ljubljana in cooperation with the Austrian Academy of Sciences. Its main objectives were to clarify stratigraphy and obtain samples for radiocarbon dating and genetic analyses. The present monograph primarily examines the Pleistocene faunal finds, especially the cave bear findings. They are attributed to a cave species that until now is known only in the high Alps. A previously published summary of the scientific results of the Neolithic finds is also included. Ajdovska jama is also of great zoological importance. It is the home of a large colony of Mediterranean horseshoe bats, which is an endangered species. Hence, the monograph concludes with an article about the life of these bats in the cave.