Janello Torriani, known in the Spanish-speaking world as Juanelo Turriano (Cremona, Italy ca. 1500 – Toledo, Spain 1585), is the greatest among Renaissance inventors and constructors of machines. Contemporary literates and mathematicians celebrated Janello Torriani and his creations in their writings. It is striking how such fame turned into nearly complete oblivion, leaving only a few clues of a blurred and distorted memory dispersed here and there. This book wishes to show the central role that artisans formed in the Vitruvian tradition played in demonstrating through practical mathematics an increasing and positive control over Nature, a step rooted in humanist culture and foundational for the understanding of those historical processes known as the Scientific and the Industrial Revolutions.