Barely a dozen letters of the alphabet suffice to categorize every star in the cosmos, but when it comes to naming and classifying living things, the job gets more complicated. As Jason Roberts reveals in this vibrant scientific saga, taxonomists take up their mission with a mix of insight and foresight, colored by their moment in history, not to mention their foibles, their vanity, and their all-too-human prejudices. The thousands of definitive two-part labels given to plants and animals since the 18th century tell a story at once important, outrageous, enlightening, entertaining, enduring, and still evolving.