With classic style and without ever losing objectivity, Hans Eberhard Mayer presents a complete and rigorous overview of the history of the crusades that includes new and well-founded interpretations that often modify the points of view that had been held to date. . In its pages, topics are analyzed such as the role played by indulgences in the origin of this movement, the socioeconomic articulation of the conquered territories, the role of the crusades in the configuration of relations between Byzantium and Western Europe, or the interested use which made them the expansive commercial policy of the Italian maritime republics. This book, a translation of the eighth German edition, also echoes the abundant bibliography that has appeared in recent years and integrates the results of the most recent research, offering an update on a topic that has always aroused the interest of historians and the public.