Ivan P. Pavlov was a pioneering Russian physiologist whose influence on Russian psychology was politically emphasized in 1930s to 1950s. He was a brilliant experimenter who received 1904 Nobel Prize in Physiology or Medicine for his work on the digestive system. Less is known about his epistemology of generalization that made it possible to study one individual for the sake of obtaining generalized knowledge. In this volume we analyze the major contributions of Pavlov from the standpoint of idiographic science, and demonstrate how generalizations in science are possible from single specimens.