Riley-Smith's 1986 book gives convincing case for a 'revisionist' view of the crusades, challenging the common belief that the crusades were motivated by fanaticism and were designed to plunder the Holy Lands. After studying handwritten documents held in churches across Western Europe in which crusaders explained their personal reasons for heading out on the "holy war," he pioneered the use of computer spreadsheets to cross-reference data on individual crusaders and their families allowing him to paint a much more complete picture than had been possible previously. Riley-Smith determined that most crusaders were motivated by spiritual devotion and a genuine desire to atone for past sins.