Originally formed by Prince Frederico Cesi in the early 17th century and later acquired by Cassiano, this group of drawings constitutes a scientific study of fossilized woods. The drawings include specimens of wood and animal fossils, pyrites and baked clays, and a series of field drawings giving the sites where these specimens were found. The introductory essays discuss the background to Cesi’s project, together with the importance of the drawings to the history of 17th century culture and science.