Like the iPad, this scientific book from 1678 has a smart cover. The front of the sheepskin bookbinding is not filled with blind-stamped decoration, as was often the case, but a printed sundial was pasted on it. Put the book in the sun, place a stylus on the cover, and it will tell you what time it is. What’s more, it was likely used in this fashion given that the ‘footprint’ of the stylus is still visible - note the small circle and the black stain near the letters IHS. A book that tells the time: the smart cover is not the only parallel with our modern iPad!
Pic: Oxford, Bodleian Library, Broxb. 46.10 (1678). More information: about this type of sundial here; more about this book here.