Bau was trained as a graphic artist at the January Matejko Academy of Fine Arts in Krakow, Poland. His education was interrupted by World World War II and he was transferred to the Krakow-Płaszów concentration camp in late 1941. Having a talent in gothic lettering, he was employed in the camp for making signs and maps for the Germans.
While in Plaszow, Bau created a miniature - the size of his hand - illustrated book with his own poetry.
He also forged documents and identity papers for people who managed to escape from the camp. During his imprisonment, Bau fell in love with another inmate, Rebecca Tennenbaum.
They were secretly married, despite prohibition by the Germans, in the women"s barracks of Plaszow. After Płaszów, Bau was transferred to Gross-Rosen concentration camp and then to Schindler"s camp where he stayed until the end of the war.
After liberation, Bau graduated from the University of Plastic Arts in KrakóWest
Bau opened his own studio in 1956 in Tel Aviv. He was well known for drawing titles for almost all Israeli movies in the 1960s and 70s. At the same time, he authored a number of Hebrew books and continued to write poetry.