The sheer scale of the Holocaust disaster is very difficult for historians to comment on because of the inconceivable brutality of the event. It is such a sensitive issue for historians because many people struggle to understand how such atrocities could have been committed in a seemingly civilised country. Another problem facing historians is the lack of clear-cut evidence on the subject. The chaotic nature of the Nazi State and the fact that they tried to keep the holocaust secret are reasons for this lack of evidence. In addition, the extermination camps were in fairly remote areas of Germany.

A major contributing factor to the Holocaust was the 'Euthanasia' or 'mercy killings' of the mentally and physically handicapped in September 1939. This programme was given the codename Aktion T4. The order to start this secret programme was in a document that carried Hitler's signature and therefore he can be...