The bookwheel (also written book wheel and sometimes called a reading wheel) is a type of rotating bookcase designed to allow one person to read a variety of heavy books in one location with ease. The books are rotated vertically similar to the motion of a water wheel, as opposed to rotating on a flat table surface. The design for the bookwheel originally appeared in a 16th-century illustration by Agostino Ramelli, at a time when large books posed practical problems for readers. Ramelli's design influenced other engineers and, though now obsolete, inspires modern artists and historians.
The bookwheel, in its most commonly seen form, was invented by Italian military engineer Agostino Ramelli in 1588, presented as one of the 195 designs in Le diverse et artificiose machine del Capitano Agostino Ramelli (The various and ingenious machines of Captain Agostino Ramelli). To ensure that the books remained at a constant angle, Ramelli incorporated an epicyclic gearing arrangement, a complex device that had only previously been used in astronomical clocks. Ramelli's design is unnecessarily elaborate, as he likely understood that gravity could have worked just as effectively (as it does with a Ferris wheel, invented centuries later), but the gearing system allowed him to display his mathematical prowess. While other people would go on to build bookwheels based on Ramelli's design, Ramelli did not in fact ever construct his own.
To what extent bookwheels were appreciated for their convenience versus their aesthetic qualities remains a matter of speculation according to modern American engineer Henry Petroski. Ramelli himself described the bookwheel as a "beautiful and ingenious machine, very useful and convenient for anybody who takes pleasure in study, especially for those who are indisposed and tormented by gout." Ramelli's reference to gout, a condition that impairs mobility, demonstrates the appeal of a device that allows access to several books while seated. However, Petroski notes that Ramelli's illustration lacks space for writing and other scholarly work, and that the "fanciful wheel" may not have been appropriate for any activity beyond reading.
While the design of the bookwheel is commonly credited to Ramelli, some historians dispute that he was the first to invent such a device. Joseph Needham, a historian of Chinese technology, stated that revolving bookcases, though not vertically oriented, had their origins in China "perhaps a thousand years before Ramelli's design was taken there."
The bookwheel was an early attempt to solve the problem of managing increasingly numerous printed works, which were typically large and heavy in Ramelli's time. It has been called one of the earliest "information retrieval" devices, and has been considered a precursor to modern technologies, such as hypertext and e-readers, that allow readers to store and cross-reference large amounts of information. Other inventors, such as French inventor Nicolas Grollier de Servière (1596-1689), proposed their own variations on Ramelli's design.
Of the dozens of bookwheels built in the 17th and 18th centuries, 14 are extant: in Ghent, Hamburg, Klosterneuburg, Cracow, Lambach, Leiden, Naples (2), Paris, Prague (2), Puebla City, Wernigerode and in Wolfenbüttel.
In contemporary times, the bookwheel is valued for its historical importance, decorative appeal, and symbolic significance. Ramelli's design has been recreated by artists such as Daniel Libeskind, and inspired the name of the Smithsonian Library's blog "Turning the Book Wheel".