Goreme and Sahinefendi collects the results of surveys conducted by the Team for Underground Studies in Turkey in these two specific areas of Cappadocia, complemented by documentation produced in collaboration with Ukrainian, French and Turkish researchers. The object was the identification and documentation of underground architecture complementary to the best-known and most substantial Byzantine rock-cut churches. This research, conducted through speleological techniques and archaeometric survey, has allowed, in particular, the discovery of numerous defensive structures, previously completely unknown, and of related underground hydraulic systems. A completely new picture of the areas investigated emerges, in which the liturgical and funerary structures carved into the rocks represent only the tip of a 'stone iceberg', that is, the most evident and closest part to the surface of an underground world that has proved to be much more extensive and diverse than previously imagined.