Dachau concentration camp held the largest number of Catholic priests-more than 2400-in the Nazi camp system. They came from two dozen countries, from every background-parish priests and prelates, monks and friars, teachers and missionaries. Over one-third were killed. Among the survivors was Fr. Johannes Lenz, who was asked by his superiors to write an account of what he saw. This book was the stunning result. An immediate sensation, it was quickly translated into English, French, Spanish and Italian. Catholic reviewers and churchmen alike were awestruck.