My dissertation traces the history of a secular ethics movement in Germany whose practitioners sought to solve a widely perceived moral crisis in the late nineteenth century. Although extant in all western countries, the ethics debate in Germany distinguished itself by what became an all-consuming preoccupation with the human will. The German ethics movement was consequently exemplary, I argue, of a German intellectual Sonderweg. That said, the movement itself was not monolithic, but divided into two antagonistic camps. One camp championed the individual will (and thus, individual moral conscience) as the ultimate source of moral values whereas the other camp insisted on the moral authority of a purportedly "collective" will. My dissertation analyzes the lives and works of two leaders of the movement: psychologist Wilhelm Wundt and sociologist Ferdinand Tönnies. And it concludes with a discussion of the movement's transformation into a "cult," which dictated collective submission to the will of a supreme leader, as it spread to ever more popular, less rarefied segments of the German people. This "collectivist" strain, represented by Wundt, came to predominate in World War I, driving the "individualist" variant, exemplified by Tönnies, underground and out of view. The Nazi regime later coopted the new faith, presenting Hitler as the embodiment of the will of the German people. Much of the popular euphoria which greeted the Nazis, I argue, had to do with the Germans' perception that their deliverance from existential pain and uncertainty had finally arrived, a perception born of an inversion of values rendered palatable by a body of scholarship originally intended as a blueprint for social comity.