We introduce some of the 96 books of scientific content, published in the 16th century and belonging to the Istituto Lombardo library. We chose some books in the field of the “natural sciences” both for iconographic peculiarities and for the original content. The library owns the first edition of the anatomy treatise of Andrea Vesalio. The medical books of Jean Francois Fernel, Antonio Fracanzani, Girolamo Fracastoro, the botanical treatise of Pier Andrea Mattioli and the geographical treatise of Giovan Battista Ramusio although in further edition are of great interest in order to evaluate the state of the art and the evolutionary steps of the science. Some books are rather rare and precious and deserve to be accurately exploited. Also the texts should be worthy of a critical investigation, overcoming the linguistic difficulties, both for the latin and for italian texts.