Nikolaas Tinbergen won a Nobel Prize in 1973 for his pioneering studies in animal behavior. The Study of Instinct, Tinbergen's first major work, introduced the subject of ethology to an American audience more than forty years ago, and it is still considered one of the best introductions to the field. Long out of print, this reissue of the 1969 edition allows a new generation of readers to explore this classic for themselves. In The Study of Instinct, Tinbergen attempts to organize the study of animal behavior into a coherent whole, focusing on how animals behave in response to stimuli, how physical and neurological characteristics shape instinct, how individual animals develop behavioral patterns, and how they adapt to changing conditions. He illustrates his discussion with fascinating examples taken from his own and other scientists' study of animals. Many of his renowned experiments using models of animals to test hypotheses about behavior are described, including his well-known study of the stickleback fish, in which he shows that it is indeed the red color of their undersides that allows males to single each other out for attack during their springtime competition.