During the twelfth century, three new schools of Daoism were founded in North China: Quanzhen (Complete Perfection), Taiyi (Supreme Unity), and Dadao (Great Way). While Quanzhen has received much scholarly attention, the others have been largely ignored. By focusing on just one school--Dadao--as in depth as possible and within the historical context, I hope to elucidate the flourishing state of Daoism in North China during the twelfth through fourteenth centuries beyond just the activity of the Quanzhen school. To that end, I have amassed sixteen inscriptions and records, as well as reconstructed one inscription previously incomplete, and added them to the eleven inscriptions and records published in the Daojia jinshi lüe and the three pieces of Yuan-dynasty poetry and prose contained in the Nan Song chu Hebei xin Daojiao kao. This has doubled the available source material. Most of these have been previously published individually, but have never been studied in conjunction with the other known Dadao texts. The result is the most comprehensive study of the school in over seventy-five years, in which I also present a new understanding of the school’s founder, how the lineages developed, and the school’s ultimate fate. The portrait of the school which emerges from this dissertation challenges the notion that Dadao was nothing more than a minor variation of the Quanzhen school or is otherwise unworthy of scholarly attention.