Why was Albert Einstein called the "Man of the 20th Century"? Einstein initiated a revolution in physics and was politically influential as a radical democrat. He is understood as a person who also has darker sides. The relationship with his mother and the love affair with Betty Neumann are systematically analyzed for the first time. New research allows for the tracing of the life paths of many of Einstein's close relatives. Visits to relatives in Ulm in 1913 and 1923 reveal the private individual Einstein and his fundamental attitudes towards others. He later saved many family members and friends from persecution by the Nazis through guarantees and recommendations. The cosmopolitan Einstein lived in Europe and the USA. His nonconformism consistently reflected critically on the society surrounding him.