This encyclopedia contains 351 entries exploring a multidisciplinary range of topics dealing with natural caves and karst landscapes, defined within as "terrain with distinctive hydrology and landforms arising from the combination of high rock solubility and well-developed solution channel (secondary) porosity underground. The encyclopedia strives to fairly represent all the regions of cave and karst locations. The entries are presented alphabetically and also listed under the following themes: archaeology, art in caves, and paleontology; biospeleology (including ecology, fauna, and other biological topics); caves and caving; cave and karst regions; conservation and management; geoscience; history; and resources and development.