 To most modern readers, it would stretch definitions to include someone like Giovan Battista Della Porta (1535–1615) in an encyclopedia of philosophy. Yet philosophy in Porta’s time encompassed a far wider range of topics than it does today, including cosmology, meteorology, and physics; biology and human psychology; and moral philosophy and politics. As a prolific writer on topics then associated with more or less alternative currents to Aristotelian natural philosophy (Henry 2008), Porta became one of the most famous and popular figures in the intellectual life of the second half of the sixteenth century and beyond. Porta thus ranks among the many rather unorthodox philosophers and in the traditional categories of the peripatetic curriculum. In the rich intellectual ferment that eventually generated the scientific revolution of the following century, Porta constitutes a highly interesting transitional figure because he engaged with the world of objects, craft and chemical substances. From this “scientific underworld” occupied by the “professors of secrets” emerged a naturalized concept of human beings and innovative ideas about science (Smith 2009, Eamon 2011), which Porta amply (and critically) reflects.