Just one of the "various and ingenious machines" of Captain Agostino Ramelli
One of the defining features of Kindles and iPads and their fellow e-readers is their ability to store tons of books in the same place, at the same time. Which means that, thanks to these quintessentially twenty-first-century technologies, we are newly encouraged to consume our books not as long meals, but as occasional snacks: a few nibbles of Moby-Dick here, a few bites of Bossypants there. Under e-readers' influence, the linear project of book-reading -- from page 1 to page 501, sequentially -- has shifted to something much more chaotic, much more casual, much more accommodating to whimsy and whim.
Literary restlessness, though, dates back much further than the 21st century. It dates back, at least, to the 16th -- to the Italian engineer Agostino Ramelli, and to his desire for a reading interface that would allow for book-borne snacking. Ramelli, who spent his professional career creating siege machinery for the military, wanted to develop a device that would allow a reader to reference multiple books at (pretty much) the same time -- a desire made especially practical given how large and heavy books were back then.