Only four men commanded Nazi extermination (as opposed to concentration) camps. Franz Stangl was one of the. Gitta Serenys investigation of this mans mind & of the influences which shaped him has become a classic. Stangl commanded Treblinka & was found guilty of co-responsibility for the slaughter there of at least 900 000 people. Sereny after weeks of talk with him & months of further research shows us this man as he saw himself & as he was seen by many others including his wife. To horrify is not Serenys aim though horror is inevitable. She is seeking an answer to the question which beggars reason: How were human beings turned into instruments of such overwhelming evil?