The German sculptor and designer, Ruckriem began his career in a restorer's studio in Cologne (1959-61), where he learnt the techniques associated with architectural sculpture. Between 1963 and 1969, he worked in another studio close to Duren. His work in stone includes sculptures influenced by abstract artists such as Maurice Lipsi and Fritz Wotruba. His style of work changed radically in 1968, after he came into contact with Minimalism, especially the work of Carl André. Together with the Americans Richard Serra and Robert Morris, Ruckriem is considered one of the main figures in the establishing of Process Art as a response to Minimalism. After creating his first installation for a specific locale, Ruckriem began to relate his sculptures to public spaces. His work and ideas on public art were of extreme importance and exerted a strong influence on 20th century. Between 1972 and 1992, he took part in Documenta 5, 7, 8 and 9 in Kassel and, in 1978, he took part in the Venice Biennale with four dolomite stones. In his sculptures, in which he favoured the use of various types of granite, after 1980, he continued to apply innovative techniques in terms of materials, scale and proportion. In 1978, he produced a series of works on paper in which he dealt with simple geometrical forms similar to those used in sculpture.