This book is brief but brilliant. Sterling Professor of History at Yale and author of several incisive studies of Puritanism, Edmund S. Morgan has written a work which in the descriptive language of the seventeenth century might be entitled, ""The Reader of Colonial History's Vade Mecum: A Brief and Illuminating Prolegomena to the Mind and Thought of the Illustrious Mr. Roger Williams, Puritan Divine and Original Thinker."" When several years ago the complete writings of Roger Williams were reissued, Professor Morgan read them ""consecutively and systematically,"" recognized that he and other historians had misunderstood and misjudged the man. ""Although Williams usually wrote polemically, in the heat of the contests of his day, his ideas exhibit an intricate and beautiful symmetry, broken only on rare occasions when he succumbed to the temptation to argue from a position that he had himself rejected but knew that his opponents accepted."" The author successfully reconstructs the course of Williams' thought and exposes the symmetry of the ideas that lay behind the polemics by placing these ideas within the context of the seventeenth century. His opening sections on Puritanism form one of the best introductions to that subject yet written. A first rate study in the history of ideas.