EN
Collections of recipes, called 'ricettari' in Italian, containing instructions on how to prepare medications, cosmetics and various substances used every day in households, were part of popular functional literature. They were complied already in the Antiquity and flourished in the Renaissance. Among books such as the often revived 'Libri di secreti' by Leonardo Fioravanti or works by Girolamo Ruscelli there is a book entitled 'I secreti...' that contains the results of Isabella Cortese's work as an apothecary and alchemist. The book was extremely popular, which is confirmed by the fact that between 1561 and 1677 it was published in nineteen editions, including three German ones. The recipes in 'I secreti...' seem to draw mainly on the achievements of alchemy and hermetic philosophy at the time. The book is also an interesting testimony to 16th century practical knowledge; it provides us with information on how everyday problems, including medical problems, were solved in those days. A copy of Signora Cortese's 'I secreti...' published in 1574 can be found in the collection of the Warsaw University Library. Its detailed description is the main subject of the present article.