Book excerpt: An in-depth portrait of the Crusades-era Mediterranean world, and a new understanding of the forces that shaped the Mediterranean world of 1050-1200. We experience the sights and sounds of the region just as enlightened Islamic empires and primitive Christendom began to contest it. We learn about the siege tactics, theological disputes, and poetry of this enthralling time. And we see that people ofdifferent faiths coexisted far more frequently than we are commonly told. Catlos's meticulous reconstruction of the era allows him to stunningly overturn our most basic assumption about it: that it was defined by religious extremism. He brings to light many figures who were accepted as rulers by their ostensible foes.