Robert Irwin began his career in the 1950s as an abstract painter. As a pioneer of the Light and Space movement in Los Angeles in the 1970s and early '80s, Irwin focused on exploring aesthetic perception as the fundamental feature of art, culminating in what he terms "conditional art" or "site-conditioned work." In addition to being a prolific artist, Irwin has been an active writer throughout his career. This book-now in paperback-includes previously published pieces along with a significant selection of writings published for the first time. The book makes clear that writing as a reflection on aesthetic questions is an integral element of Irwin's multifaceted art practice.