Les animaux dénaturés is a 1952 novel by Jean Bruller under his pseudonym Vercors. English-language editions appeared under the titles You Shall Know Them, The Murder of the Missing Link, and Borderline. The author adapted it into a play, Zoo ou l'Assassin philanthrope. The novel was adapted into the motion picture Skullduggery (1970), starring Burt Reynolds. Source: Wikipedia (en)