Yeshiva teaching in the modern period famously relied on memorization of the most important texts, but a few medieval Hebrew manu-scripts from the twelfth or thirteenth centuries include examples of alphabetical lists of words with the biblical phrases in which they occurred, but without pre-cise locations in the Bible—presumably because the learned would know them.

Ebooks don’t have those limitations, both because of how readily new editions can be created and how simple it is to push “updates” to existing editions after the fact. Consider the experience of Philip Howard, who sat down to read a printed edition of War and Peace in 2010. Halfway through reading the brick-size tome, he purchased a 99-cent electronic edition for his Nook e-reader:As I was reading, I came across this sentence: “It was as if a light had been Nookd in a carved and painted lantern …” Thinking this was simply a glitch in the software, I ignored the intrusive word and continued reading. Some pages later I encountered the rogue word again. With my third encounter I decided to retrieve my hard cover book and find the original (well, the translated) text. For the sentence above I discovered this genuine translation: “It was as if a light had been kindled in a carved and painted lantern …”A search of this Nook version of the book confirmed it: Every instance of the word kindle had been replaced by nook, in perhaps an attempt to alter a previously made Kindle version of the book for Nook use. Here are some screenshots I took at the time:It is only a matter of time before the retroactive malleability of these forms of publishing becomes a new area of pressure and regulation for content censorship. If a book contains a passage that someone believes to be defamatory, the aggrieved person can sue over it—and receive monetary damages if they’re right. Rarely is the book’s existence itself called into question, if only because of the difficulty of putting the cat back into the bag after publishing.