The creative dark is a term by Doris Lessing to describe the process of writing. It is used here also to describe writing about subjects that are commonly held to be unknowable: namely, writing fiction about the Holocaust, trauma and autism. Yesterday’s Shadow is a novel, which explores a link between autism and the Holocaust. Bruno Bettelheim, a psychologist, was interred in Dachau and Buchenwald in 1938 – 1939. His observations on human behaviour in the camp led him to hypothesise that autistic children were like the Musselmänner in the camps, they had withdrawn from the world through lack of hope. Bettelheim furthermore claimed that autistic children had no hope because the parents did not love them. This came to be known as the ‘refrigerator mother’ hypothesis. The novel considers the differences between the developmental disorder of autism and autistic-like withdrawal, which may happen as a result of trauma. Several issues arose during the writing of the novel and these are addressed in the commentary. The first of these is memory, in particular how trauma is remembered. Following a brief outline of psychological research in this area, there is a discussion of how memory and trauma are treated in Yesterday’s Shadow and in the discredited memoir by Binjamin Wilkomirski, Fragments. The second factor concerns women’s experience of the Holocaust and whether there is a case for stating that women’s experiences were different from those of men. This is discussed in relation to Yesterday’s Shadow and Lovely Green Eyes, a novel by Arnošt Lustig. Finally, there is an exploration of how the Holocaust is represented and the ethical issues surrounding this. One significant theme is a need for historical accuracy when writing about the Holocaust. A recent children’s novel, The Boy in the Striped Pyjamas, by John Boyne is discussed in this light.