this is a fine and fruitful moment for thinking about cartography. There are whole relatively new genres, from the M.R.I. to video-game landscapes to social media-based graphics that depict trending tweets and online conversations.
It could be argued that a ghostly, cobwebby apparition produced by Facebook, generated by Facebook users’ connections, is too different from a map produced by Eratosthenes of Cyrene for the Great Library of Alexandria to coexist in the same book. But Mr. Garfield prefers skipping and sampling. His chapters are mere snippets, and his book’s guiding principle is casual fun — to the extent that it even has one.