Coelum philosophorum

Paracelsus (1493-1551) was a famous German-Swiss alchemist and physician, botanist, author of several ancient works on medicine, reformer, who established the role of chemistry in medicine.  Born Philippus Aureolus Theophrastus Bombastus von Hohenheim, after some years of seeking medical knowledge he gave himself the Latin name of Paracelsus, meaning "greater than Celus." Assumed his new name Paracelsus bravely announced that his medicine was greater than that of the ancient Greeks and Romans.
Coellum Philosophorum is and alchemic tract by Paracelsus. It is a compilation of various basic principles of alchemy; it describes properties of various substances and elements, clarifies basic principles and laws that work within this field of science, and speculates on its moral aspects. If alchemy and medieval science is of any interest for you, than this short tract is a must read, along with other Paracelsus’s works and publications.