Soldiers of the Faith by Ronald C. Finucane (1984, Hardcover)

This work "Soldiers of the Faith: Crusaders and Moslems at War" written by a Research Fellow in the Graduate Center for Medieval studies at Reading University here delves into the Crusades and aims at the more common individual who took up the Cross. In it's day it was a selection by the exclusive History Book Club. A scholarly work but not quite as complicated as Runicman's "History of the Crusades".
It is well written, interesting and does not lag in telling the story. It was also one of the first works to cover the Moslem interactions with the West. Including Women, Jews, Christians and how they were treated during these events.
A useful work, even by the research scholar, for reference concerning the time period.