Read: The one-of-a-kind treasure of a 3-D type book
Large sheets of paper were printed with male and female figures and a small amount of explanatory text. Flaps of paper representing different organs were pasted in layers on top of the figures. The top flap represented the skin and external anatomy; when it was down flat, the figures looked like ordinary nudes. By lifting the flaps, the viewer performed a virtual dissection, revealing successive layers of internal organs. The top flap was most commonly lifted from the crotch region of the figures, adding an erotic frisson that undoubtedly contributed to their enormous popularity.
Flap anatomies also appeared inside medical books. In 1583, the German surgeon and eye doctor Georg Bartisch published Opthamoduleia, a massive tome on diseases of the eye and their treatments. He included two flap anatomies in the text. The first showed the anatomy of the brain: The viewer lifted the skin and hair, the skull, and the cerebrum to reveal the brain stem and optic nerves. The second was a seven-layer anatomy of the eye. The French philosopher René Descartes also included a flap anatomy of the heart and lungs in his Treatise of Man of 1664.
The most elaborate flap anatomies are found in the works of the Dutch anatomist Johann Remmelin, whose book Microcosmic Mirror went through multiple editions from 1613 to 1744. Most contain three pages of flap anatomies: The first has a male and a female figure and a pregnant torso, the second a male figure, and the third a female figure. These all have multiple sets of flaps, many of which open in different directions and have printing on both sides.
Pop-ups weren’t completely unique to printed scientific books. Printers exploited wheels and flaps for a variety of uses, like games of chance, the creation of codes, and mildly salacious prints that allowed the reader to lift up a courtesan’s skirt and see her undergarments. But it took until the early 19th century for pop-ups, flaps, wheels, tabs, and other moving parts to become a feature of children’s books.
Pop-up science texts were a creative response to the demands of an expanding base of readers, hungry for information about the natural world. The appetite for such books remains strong today, as the popularity of books by Neil deGrasse Tyson and Stephen Hawking demonstrates. Although Tyson and Hawking do not include movable paper parts in their books, they grapple with the same challenge their forebears faced: how to make scientific subjects accessible to general readers.
Pop-ups are no longer used to do this, in part because of changes in print technology. But at a deeper level, the abandonment of flaps and volvelles and their ilk in books for adults also reflects changes in reading practices. Modern readers think of reading primarily as a mental activity. Earlier readers saw it as a physical activity as well. They did not just turn the pages of their books. They wrote in the margins, underlined and annotated, used blank space for recipes and handwriting practice, kissed religious images, and copied out quotes. Pop-up science books evoke a period in which reading always meant physical engagement, and they remind us that reading was—and still is—an embodied experience.