Inner Worlds examines the emergence and operation of representations of interiority—consciousness, “folk mind,” “spirit”—in Japan from its industrial revolution to the rise of fascism during the interwar period. These representations functioned to reproduce the capitalist system by containing its excesses. Thus, poverty in the 1880s was ostensibly the result of defects in one’s innate mental character. A degenerate “crowd mind” explained the strikes and riots of the early twentieth century. State subversion during the 1930s supposedly reflected an attenuated “folk spirit.” By locating the roots of capitalism’s excesses not within the socioeconomic order itself but within a defective interiority, ideologies of interiority operated to contain disruptions to Japan’s socioeconomic order, conceal its defects, and sustain the capitalist system. In short, Inner Worlds reveals how interiority was constituted in ways consistent with both the demands of the emerging capitalist order of the late nineteenth century and the conditions that coalesced to form a fascist conjecture in the 1930s.