Irwin's exploration of perception and experience dates back to the beginning of his career as an Abstract-Expressionist painter in Los Angeles in the 1950s. Soon plagued with doubts about the adequacy of the panel painting as a depiction of reality, in the 1960s he pioneered the Californian Light and Space movement, which also included Larry Bell, John McCracken, James Turrell, and Doug Wheeler. Using Plexiglas, translucent fabrics, reflecting surfaces, and fluorescent tubes he sought to forge a connection between his works and their environment. A central question that ushered in a change of paradigm in his work was: "What kind of a 'reality' was this that allowed itself such abstraction as to demand that the world end at the edge of my canvas? Yet what kind of a world would it be if there were no such limits?"In his efforts to find an art form not limited by the size of the canvas, Irwin in 1970 gave up his studio and with it the idea of art defined by its status as an object in favor of art as a phenomenon. Since then he has been realizing works that he calls "site-conditioned." Unlike "site-dominated," "site-adapted," and "site-specific" works, which refer to and involve a specific location but remain self-contained works of art, his installations only become phenomena in response to the space surrounding them and the conditions prevailing there. This makes it impossible to transfer them to some other location. An inherent quality of these works is their ability to transcend the boundaries between art and architecture, art and landscape, art and urban planning, and art and utility. Robert Irwin's artistic work has always been accompanied by theoretical philosophical considerations and questions on the function of aesthetics, perception and surroundings, which the artist carried out in numerous texts and lectures. This book publishes a key text on his idea of "conditional art," "Being and Circumstance" - for the first time in German translation.