Bursting out of the frame and off the pedestal, installation art has proven to be one of the most vital artistic innovations of the past century. Its practitioners—including Robert Smithson, Mike Kelley, and Yayoi Kusama—appreciate its anything-goes sensibility and relative absence of historical baggage. Individual installations may take the form of architectural interventions, taxonomic collections, or large-scale landscaping projects, but they have in common a search for a new kind of aesthetic experience. The following boundary-breaking examples are excerpted in their entirety from Phaidon’s The Art Book.