Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Excellent book

Riley-Smith, widely acknowledged as an expert in Crusade studies, has presented here a book which is not a dry recitation of Crusade facts but instead an examination of motives behind the Crusade: WHY did the Crusading knights choose to heed Urban's call and head off into a strange land to fight? WHY did Urban issue that call in the first place? What were the kinds of hardships a Crusader might have faced?This is an extremely well-written, well-researched book and I would recommend it to anyone interested in the fields of medieval or Crusade studies.