"Tadeusz Borowski, Jean-Francois Steiner, Olga Lengyel, Eugen Kogon, Andre Schwarz-Bart, Elie Wiesel and Bruno Bettelheim"

These are all writers who describe the Nazi concentration camps, either through memoirs or literature based on their experiences. There is a school of thought within Holocaust theory that only those with direct first-hand experience of the Holocaust should write about it, as people without such experience cannot possibly hope to understand the truth of these horrific events. 'Outsider' writers like William Styron are accused of using the Holocaust simply as literary material, like any other subject. In this passage, Styron is answering such criticism.