The collection of the former Cologne gallery owner and collector Rolf Ricke is focused on works of American Post-Minimalism and Conceptual Art. Assembled from the 1960s onwards in close cooperation with the artists, most of whom came from the New York art scene, it not only played a pioneering role in the European reception of contemporary American art; it also contains a large number of works of art-historical importance. Included are works by Richard Serra, Keith Sonnier, Gary Kuehn, and Lee Lozano as well as artists of the next generation such as Steven Parrino, Carl Ostendarp, and Thom Merrick. In 2006, the MMK acquired the collection in conjunction with the Kunstmuseum Liechtenstein and the Kunstmuseum St. Gallen. In many respects, it builds on the museum’s existing collection, enriching it by adding a range of new resonances and relationships.