This chapter first establishes the historical context for the emergence of Eison’s Saidaiji order of monks and nuns (later known as the Shingon Ritsu school) and outlines their diverse contributions to Kamakura-period (1185-1333) religion and society. In particular, I investigate the Saidaiji order’s involvement in the Mañjuśrī cult and the twofold engagement with marginalized people and elites that is characteristic of those cultic activities. Next, I summarize the contents of the ensuing chapters and analyze the historiographical issues motivating this study. I argue that a lingering privileging of the traditionally understood “New Kamakura Buddhism” of the Pure Land, Zen, and Nichiren schools—evident even in such revisionist models of medieval Japanese religion as Kuroda Toshio’s theory of the “exoteric-esoteric system” (kenmitsu taisei)—continues to hamper the study of Eison’s and other medieval Nara Buddhist movements. I then show how this study aims to redress these biases.