Every piece of technology has a precedent. Most have several different types of precedents. You’ve probably used (and may well own) an eBook reader, for instance, but what would have afforded you a selection of reading material two or three centuries ago? If you were a Jacobean Englishman of means, you might have used the kind of traveling library we featured in August, a handsome portable case custom-made for your books. (If you’re Tom Stoppard in the 21st century, you still do.) If you were Napoleon, who seemed to love books as much as he loved military power — he didn’t just amass a vast collection of them, but kept a personal librarian to oversee it — you’d take it a big step further. …