Yoritomo and the Founding of the First Bakufu - The Origins of Dual Government in Japan - Jeffrey P. Mass
This book is a much expanded and wholly rewritten treatment of the subject of the author's first book, Warrior Government in Early Medieval Japan, published in 1974. In this new version, the \warrior\ and \medieval\ character of Japan's first shogunate is significantly de-emphasized, thus requiring not only a new title, but also a new book.