In Slippery Beast, journalist Ellen Ruppel Shell travels in the world of “eel people,” pursuing a burgeoning fascination with this mysterious and highly coveted creature. Despite centuries of study by celebrated thinkers from Aristotle to Leeuwenhoek to a young Sigmund Freud, much about eels remains unknown, including exactly how eels beget other eels. Eels cannot be bred reliably in captivity, and as a result, infant eels are unbelievably valuable. A pound of the tiny, translucent, bug-eyed “elvers” caught in the cold fresh waters of Maine can command 3,000 or more on the black market. Illegal trade in eels is an international scandal measured in billions of dollars every year. In Maine, federal investigators have risked their lives to bust poaching rings, including the notorious half-decade-long “Operation Broken Glass.” Ruppel Shell follows the elusive eel from Maine to the Sargasso Sea and back, stalking riversides, fishing holes, laboratories, restaurants, courtrooms, and America’s first commercial eel “family farm,” which just might upend the international market and save a state.