In the last chapter of this section the spectrum of medieval written culture expands once again, not just in the material sense, but also regarding the kind of book under scrutiny: for once, the discussion includes objects from the era of print. Here we examine books with remarkable tools and instruments physically attached to them, a genre that is both rare and versatile—and, frankly, a bit weird as well. Mounted onto the page or the bookbinding, these added instruments extended the book's primary function as an object that one reads into a utilitarian piece of hardware. Some of these add-ons functioned as a calculator, others—astonishingly—even allowed the reader to tell time. As unusual as this enhanced functionality was in the Middle Ages, to a modern person it seems very familiar. Apps on our smartphones, after all, do precisely the same: they extend the function of the phone far beyond its original parameters. Let's examine how medieval books were sometimes more than books.

The Volvelle

The most common piece of “hardware” added to the book is a calculation tool named a “volvelle.” It breaks with the tradition that a book provides 2D information, because it consists of one or more rotating disks mounted on the page (Figure 104). Volvelles allowed the reader to make a variety of complex calculations, such as the position of the sun and the moon, or the precise date of Easter—which, like the volvelle, moved. The oldest volvelles are connected to the scientific explorations of Ramón Llull, a thirteenth-century scholar working in the kingdom of Majorca, who imported the clever device from Arabic scholarly culture. He introduced them in his Ars Magna (The Great Art) of ca. 1305. This explains why the earliest volvelles date from the fourteenth century (there are no older manuscripts that hold them, as far as I am aware), as well as why the oldest ones are found in books holding works by Llull. The reason why he included these devices is very medieval but also speaks to the curiosity of scholars in the thirteenth century: Llull believed that they could provide logical answers about Creation. Llull's specimens, however, were less sophisticated than the ones shown in this chapter. They had only three discs and present less data on and around the dials.