On the Map is the One Thousand and One Nights of cartography: it feels impossible to predict what the next vignette would be. Facts and tidbits would pop up where you least expected them, such as the etymology of “limelight,” which seems inter alia puzzling for a book about maps. Before it was employed as a spotlight in theaters—or the grammatical shift into the figurative center of attention—an oxyhydrogen flame directed onto calcium oxide was created as a cartographic tool to cut through the fog and inclement weather to enable proper coastal surveys. Orienting one’s self—getting one’s bearings in a relatively novel environment or circumstance—should seem a nonsensical or meaningless phrase, unless you’ve seen ancient maps. “What we regard as north lies to the left, while east is at the top, a placing that has given us the word “orientation.’” “Gerrymander” is in there too, and it has to do with salamanders. On maps. For real.