“The thinking heart of the barracks” is how Etty Hillesum described herself when she was an inmate of a German concentration camp in World War II. She entered voluntarily to prepare herself for the inevitable end. Her diary is the story of her inner transformation, of being within herself a battlefield for the problems of our times, of finding joy and inner peace in the face of persecution, suffering and death. Love perfected her will-love for people and love for God. Her diary is one of the most detailed records of the work of love and will that makes advanced development possible.