The object of the book is to interpret, in terms that will be readily intelligible to this generation, the life and concerns of the people of a century who, to the author's mind, have done more for human progress than those of any like period in human history. There are few whose eyes are now holden as they used to be, as to the surpassing place in the history of culture of the last three centuries of the Middle Ages. Personally the author is convinced, however, that only a beginning of proper appreciation has come as yet, and he feels that the solution of many problems that are vexing the modern world, especially in the social order, are to be found in these much misunderstood ages, and above all in that culmination of medieval progress--the period from 1200 to 1300. The subject was originally taken up as a series of lectures in the extension course of the Catholic Summer School, as given each year in Lent and Advent at the Catholic Club, New York City. Portions of the material were subsequently used in lectures in many cities in this country from Portland, Me., to Portland, Ore., St. Paul, Minn., to New Orleans, La. The subject was treated _in extenso_ for the Brooklyn Institute of Arts and Sciences in 1906, after which publication was suggested. The author does not flatter himself that the book adequately represents the great period which it claims to present. The subject has been the central idea of studies in leisure moments for a dozen years, and during many wanderings in Europe but there will doubtless prove to be errors in detail, for which the author would crave the indulgence of more serious students {ix} of history. The original form in which the material was cast has influenced the style to some extent, and has made the book more wordy than it would otherwise have been, and has been the cause of certain repetitions that appear more striking in print than they seemed in manuscript. There were what seemed good reasons for not delaying publication, however, and leisure for further work at it, instead of growing, was becoming more scant. It is intrusted to the tender mercies of critics, then, and the benevolent reader, if he still may be appealed to, for the sake of the ideas it contains, in spite of their inadequate expression. PREFACE. (GEORGETOWN UNIVERSITY EDITION).