Some of the most ingenious techniques for information management in early modern Europe were devised by the compilers who composed the largest reference books, like the “Theatrum humanae vitae” and its even larger sequel, the “Magnum theatrum” (“Great Theater,” 1631). Compilers cut and pasted, very literally, with scissors and glue, from manuscript notes they had already taken — or, even more efficiently, by exploiting a new, cheap source of printed information: older editions of books.