Peter Grossmann is probably the last Berlin architect of Walter Gropius’ generation whose estate has not yet been researched. Grossmann was born in Aachen on 18 May 1888, the son of a respected master carpenter. In 1908 he moved to Berlin after being appointed by Peter Behrens to his new studio in Neubabelsberg. He worked there from 1908 to 1914, making him the office’s longest-serving employee after Jean Krämer. Behrens’ studio was the birthplace of new architecture at the time: it was here that Grossmann met all of the German master’s important collaborators: Walter Gropius, Ludwig Mies van der Rohe, Le Corbusier, Jean Krämer and many others. After the war, Grossmann opened his own office in Berlin and developed his three-group building system. Using this system, he was the first to build his own house in Berlin-Dahlem in 1922. The house still exists today in the ownership of his heirs and is an outstanding testimony to the quality of his building skills. Grossmann’s biography – his affiliation with the Catholic Church and his closeness to the Jewish community, his teaching at the Magdeburg School of Applied Arts and later, during the Nazi era, his retirement from teaching, but also the reopening of his studio after the war with urban planning proposals for the reconstruction – is exemplary for the history of the German in the 20th century. He worked in Berlin for 60 years, from 1908 to 1968. During these six decades, he was able to witness all political developments and the resulting changes in architectural taste, which he himself always interpreted very freely, as he had learned from Peter Behrens.