Conventional treatments of the Renaissance give scant attention to the mechanical devices that made possible some of the age's greatest monuments or to the inventors who envisioned the new technologies. Pamela Long's brilliant works on Renaissance technology and engineering are important exceptions, as are the extensive publications of Paolo Galluzzi, the longtime director of the Museo Galileo in Florence and leading specialist of the history of Renaissance engineering. With his latest book, Galluzzi depicts a new Italian Renaissance, a renaissance of machines. The Italian Renaissance of Machines, based on his 2014 Berenson Lectures at the Villa I Tatti in Florence, may be the most accessible contribution to Galluzzi's vast body of scholarship.

Galluzzi's subject is the Renaissance books of machines, both in manuscript and print, from the fifteenth to the early seventeenth century. Galluzzi begins with the Sienese school of engineering treatises, concentrating particularly on the work of Mariano di Jacopo, called Taccola (1382–1453), who, Galluzzi writes, was “the first effective promoter of a movement for the cultural and social recognition of technical knowledge and practice that was soon to gain widespread and lasting momentum” (2). Taccola was no engineer but was, as Galluzzi describes him, a “humanist of machines.” His ornately illustrated manuscript treatises, “De Ingeneis” and “De Machinis,” were, like most humanist works, dedicated to a hoped-for patron, in this case Emperor Sigismund of Hungary.

The Renaissance treatises on machines weren't just impressive works of art; the devices they depicted carried an important message: machines can ease the burden of human toil, and as such are symbols of power—as, for example, in a depiction of a woman effortlessly operating a suction pump to draw water from a well, to Galluzzi's knowledge the only fifteenth-century image of a woman operating a mechanical device.

The advent of linear perspective was a crucial shift in enabling artists to realistically depict complex machines. First appearing in the work of Taccola's contemporary Francesco di Giorgio, it was exploited to great effect by Leonardo da Vinci, whose machine manuscripts (the Codex Atlanticus and the Codex Arundel) are the subject of a lengthy, magisterial chapter. From Leonardo's perspective, machines weren't just useful and labor saving; they were also good to think with. Galluzzi's meticulous study of Leonardo's notebooks reveals that his intention was to understand the rules (or laws) of mechanics, and he vehemently rejected the medieval tradition of mechanics, which posited laws based on mathematical lines and imaginary weights, abstract fictions that ignore the critical reality of friction. He upheld a similar standard in his studies of optics, in particular his treatment of burning mirrors, in which he proposed to replicate Archimedes's celebrated mirror, which focused the sun's rays to set fire to Roman ships laying siege to the city of Syracuse. Leonardo's speculations about designing burning mirrors were never far removed from the gritty reality of actually making such mirrors—in other words, they were not just about geometrical optics but about designing real instruments.

In his final chapter, “Immaterial Machines,” Galluzzi treats machine books that were influenced by the humanist rediscovery of ancient treatises on architecture and mechanics, which emphasized the mathematical foundations of mechanical activities. Proponents, mostly philologists, became known as “restorers of ancient mechanics”—Niccolò Tartaglia and Guidobaldo dal Monte, among others. The obsession with geometrical principles and imaginary machines is pronounced in the so-called Theaters of Machines, lavishly illustrated treatises depicting intricate, excessively complicated mechanical devices. The Theaters of Machines promoted the image of the engineer as a magus, a maker of wondrous, almost miraculous mechanical devices. The humanist restorers of ancient mechanics dreamed of machines but never built machines; they were only interested in the geometrical principles of mechanics. It was a radical shift away from Leonardo's way of thinking about machines, and it was the pathway that culminated in Galileo's compelling treatises on mechanics.

Some of the material in The Italian Renaissance of Machines has been recycled from Galluzzi's previous publications, but many of these earlier studies (including a surfeit of exhibition catalogues) are difficult to find or out of print. This handsome volume, printed on sturdy paper and amply illustrated with high-quality images, makes readily available the central thesis of the foremost historian of Italian Renaissances mechanics.