Letters from Adolf Hitler's father give rare glimpse into dictator's upbringing Like father, like son — Adolf Hitler's father was also self-taught, smug and greatly overestimated himself, writes veteran Austrian historian Roman Sandgruber in a new book. Little was known about Alois Hitler, the father of Adolf Hitler, until now Previously unknown letters written by Adolf Hitler's father, Alois Hitler, shed light on the family origins of the Nazi dictator, reveals a new book that was published on Monday. In his German-language book "Hitler's Father: How the Son Became a Dictator," Austrian historian Roman Sandgruber argues the elder Hitler played a large role in shaping the psychology of his son.