In his 1913 behaviourist manifesto John B Watson urged psychologists to adopt "a unitary scheme of animal response...(that) recognizes no dividing line between man and brute." His call was heeded. By the 1930s, methodological behaviourism and animal behaviour research were dominant features of the psychological landscape. To document the origins of behaviourism, this series collects the theoretical and empirical articles that set the terms of the behaviourist debate. It includes the most important pre-Watsonian monographic contributions to objectivism and reprints the first full text of the new behaviourism.