This chapter describes Pavlovs life and major research achievements. It also follows research on one of the topics he was the first to investigate. Pavlov believed that his experiments on dogs contributed to understanding various aspects of human psychology. One such topic was experimental neurosis. The chapter describes how his approach influenced other researchers and eventually led to what has become a standard tool used by many clinical psychologists. Despite such interests, Pavlov always described himself as a physiologist and maintained that the main point of his experiments was to obtain greater understanding of the brain. Yet, as described in this chapter, his concept of how the brain works ignored mainstream developments in neurophysiology and was a major target for a critical admirer, the Polish scientist, Jerzy Konorski.