Robert Sullivan knows when to call a rat a rat. Equipped with little more than night-vision gear and a lot of guts, Sullivan spent the better part of a year lurking in the filth-slicked alleys of New York City, excitedly taking notes. The result is Rats: Observations on the History and Habitat of the City’s Most Unwanted Inhabitants (Bloomsbury, 2004), a hysteria-free portrait that looks beyond the bad rep. A detailed work of natural observation, Rats is gracefully written, perversely intriguing and often funny as hell. Sullivan gives us the rat facts, but he also tells rat stories, dispels rat rumours, recounts rat battles and details the War on Rats. He talks to wizened exterminators and an alley inhabitant who has managed to train a rat pack. Sullivan, a regular contributor to the New Yorker, notes that, by one estimate, rats are responsible for 26 percent of all electric-cable breaks and 18 percent of all phone-cable disruptions. Why so destructive? It turns out that rat teeth are stronger than aluminum, copper, lead and iron—comparable to steel, in fact. Amazingly, the alligator-like structure of their jaw allows them to exert a biting pressure of up to seven thousand pounds per square inch. When they’re not chewing away, rats are usually engaged in making more rats. They can have sex as many as twenty times in one day and male rats are driven to copulate with as many females as possible. “Most likely,” writes Sullivan, “if you are in New York while you are reading this sentence or even in any other major city in America, then you are in proximity to two or more rats having sex.” What emerges from Sullivan’s teeming mound of facts and stories is a portrait of New Yorkers themselves. Rats is a delightful, wise, tangential excursion into the underbelly of the city.