Clifford Paul "Cliff" Stoll (born June 4, 1950) is an American astronomer, author and teacher. He is best known for his investigation in 1986, while working as a system administrator at the Lawrence Berkeley National Laboratory, that led to the capture of hacker Markus Hess, and for Stoll's subsequent book The Cuckoo's Egg, in which he details the investigation. Stoll has written three books as well as articles in the non-specialist press (e.g., in Scientific American) on the Curta mechanical calculator and the slide rule, and is a frequent contributor to the mathematics YouTube channel Numberphile. Source: Wikipedia (en)