At some point in history, after the step was taken from legends to realistic description, a further step was taken towards scientific literature. It is based on accurate descriptions, but also contains the repetition of related knowledge and the testing of observations against these theories. And if well done, it also postulates new theories and inserts them into what is already known. Such texts are then referred to as scientific works.
In cave and karst studies, this first happened in 1665, when the German priest Athanasius Kircher wrote his book on all that is underground, Mundus subterraneus. Still written in Latin, he describes what he sees and tries to explain it without using Bible texts. The German-language work Die Ehre Deß Hertzogthums Crain by the Slovenian Johann Weichard Frh. von Valvasor was also novel. Although it was actually a geographical description, the Slovenian names used in it soon became geological terms for karstology because he was the first to make an inventory of characteristic karst forms. Many important books were written in the 19th and early 20th centuries, which are now in the public domain. This list is far from complete, but for many of these examples we can offer an ebook download.