German artist associated with both the Expressionism and New Objectivity movements. He was prolific in the area of self-portraits, painting nearly as many as Rembrandt and Picasso.
He was a medical volunteer during World War I. This traumatic experience greatly influenced his artwork. He was one of the most heralded artists of the Weimar Republic.
His work was displayed at the Brooklyn Museum and at the Metropolitan Museum of Art.
He and his second wife, Quappi, left Germany for Amsterdam after Hitler denounced his work and the work of fellow modern artists as degenerate.
He was influenced by philosopher Friedrich Nietzsche.