With his extensive oeuvre and his significant art-theoretical writings, Willi Baumeister was one of the most important German artists of Classic Modernism. During his studies with Adolf Hölzel, he first met the Oskar Schlemmer who was to become a life-long friend. The 'Mauerbilder' - panels with a wall-like relief structure, created by adding sand and putty to the paint - brought about Baumeister's international breakthrough. His oeuvre is divided into many groups of works and displays a vocabulary of form that became more and more abstract. In 1928, Baumeister was offered a chair at the Städelschule in Frankfurt; in 1930, he joined the 'Cercle Carré', and in 1931 he became a member of the artist group 'Abstraction Création'. Baumeister was ostracised as a 'degenerate' artist by the National Socialists. He then lived a secluded life, wrote, and spent his time studying prehistoric and Oriental art, which influenced his 'Eidos' pictures and 'Ideogrammes'. After the War, he resumed teaching at the Art Academy in Stuttgart.