With an emphasis on developments taking place in Germany during the nineteenth century, this book provides in-depth examinations of the key contributions made by the pioneers of scientific psychology. Their works brought measurement and mathematics into the study of the mind. Through unique analysis of measurement theory by Whewell, mathematical developments by Gauss, and theories of mental processes developed by Herbart, Weber, Fechner, Helmholtz, Müller, Delboeuf and others, this volume maps the beliefs, discoveries, and interactions that constitute the very origins of psychophysics and its offspring Experimental Psychology. Murray and Link expertly combine nuanced understanding of linguistic and historic factors to identify theoretical approaches to relating physical intensities and psychological magnitudes. With an eye to interactions and influences on future work in the field, the volume illustrates the important legacy that developments in the nineteenth century have for twentieth and twenty-first century psychologists. This detailed and engaging account fills a deep gap in the history of psychology. The Creation of Scientific Psychology will appeal to researchers, academics, and students in the fields of history of psychology, psychophysics, scientific, and mathematical psychology.