The works of Giambattista Della Porta represent the first extended and systematic textual source on the study of the optical phenomena made possible by optical artifacts, such as glass mirrors and lenses, which became available in increasing quantity during the sixteenth-century thanks to the progress in glass-making and glass-working. Although Della Porta's optical writings are of particular interest for the history of early modern optics, they have received a rather negative treatment in recent and less recent historiography. The studies collected in the present volume take a closer, unprejudiced view at Della Porta's published and unpublished attempts at making sense of optical phenomena, and aim at reassessing his role in the development of early modern optics by reconstructing both the scope and the context of his work, and by comparing it to that of his contemporaries.