Pavlov's research was foundational to the twentieth-century understanding of physiology and psychology, yet much of his work remains untranslated from the original Russian language. In this book, Olga Yokoyama sets out to translate the third volume of Pavlov's Complete Works, as well as his last unpublished paper. This volume also contains the papers from the sixth edition of Twenty Years of Objective Study of the Higher Nervous Activity of Animals, arguably the most impactful work by the 1904 Nobel Laureate. His concept of the conditional reflex has influenced human thought far beyond physiology, affecting the ways we view not only such practical matters as learning and child-rearing, but philosophical questions of the mind and its relationship to the psyche, creativity, and individual freedom. This translation is accompanied by three introductory essays which contextualize Pavlov's work from three perspectives: that of Pavlov's text as it was subjected to translation, that of neuropsychological science today, and that of the history of scientific thought and practices.