Gabo was a pioneer of the use of space and motion as primary sculptural elements, and of modern materials like plastics. His brother Pevsner was a close colleague, mentor and artistic influence. A visit to Kandinsky in Munich introduced Gabo to the idea of abstraction. Tatlin and Rodchenko (and Kandinsky) were colleagues at Vkhutemas in Moscow (Gabo was an unofficial presence), and Archipenko a fellow-exhibitor in a Berlin show that Altman helped organise. Moore, Read, and especially Nicholson and Hepworth were friends in Britain, and Mumford in the U.S. Schwitters, a close friend, dedicated a Merzbau ‘cave’ to him.