Crusading in the Age of Joinville enhances the current literature dealing with the issue of crusaders' motivations by providing a detailed examination of the ideas and experiences of those who promoted and participated in the crusades of Louis IX of France in the mid-thirteenth century. It assesses the possibilities and problems associated with the source material available to historians of crusading in the thirteenth century and highlights the unique nature and value of John of Joinville's Life of Saint Louis. Two distinct approaches are taken to the analysis of these sources in order to demonstrate their richness. The first of these is thematic and is employed to reveal contrasts between the idealised images of crusading depicted by its promoters and the experiences of those who responded to their calls to take the cross. Secondly, the careers of Joinville and his close contemporary Oliver of Termes provide extended case studies demonstrating that involvement with crusading could have very different origins and expressions. Overall, Crusading in the Age of Joinville provides an innovative and accessible study of crusaders and crusading in the thirteenth century.