Why did the Bildungsroman, defined as the novel of development, and its protagonist Youth, become the symbolic form of the US's cultural preoccupation with regional difference amidst the nation's rapid but uneven development c. 1900-1960? As a genre that historically represented the young individual's development in national-historical time, the Bildungsroman became one crucial means of configuring the culturally, politically, and economically asymmetrical effects of national modernization and the US's political ascendence within the capitalist world-system. Responding to that predicament, the novel of uneven development rose to salience, led by its protagonist, the unfixed youth, whose development within the national-historical time of Americanization is unsettled by their preoccupation with regional difference: an immobilizing entanglement I call American literature's regional complex. This book maps four prominent variations across the Midwest, Northeast, South, and Southwest that responded to that uneven development, fragmenting, and ultimately denying the Bildungsroman's consolidation into a coherent nationalist form.