Eugen Kogon was a German historian and Nazi concentration camp survivor. A well-known Christian opponent of the Nazi Party, Kogon was arrested more than once and spent six years at Buchenwald concentration camp. Known in Germany as a journalist, sociologist, political scientist, author, and politician, he went on to be considered one of the "intellectual fathers" of both West Germany and European integration. His 1946 book The Theory and Practice of Hell still stands as a basic reference on Nazi crimes.

Stéphane Frédéric Hessel was a French diplomat, ambassador, writer, concentration camp survivor, Resistance member and BCRA agent. Born German, he became a naturalised French citizen in 1939. He became an observer of the editing of the Universal Declaration of Human Rights of 1948. In 2011 he was named by Foreign Policy magazine in its list of top global thinkers. In later years his activism focused on economic inequalities, the Israeli–Palestinian conflict and protection for the post–World War II social vision. His short book Time for Outrage! sold 4.5 million copies worldwide. Hessel and his book were linked and cited as an inspiration for the Spanish Indignados, the Arab Spring, the American Occupy Wall Street movement and other political movements.