This publication is devoted to the relationship between two contrasting works by light artist James Turrell (*1943 in Los Angeles): Architectures of Light and Skyspaces, which explore the encounter between the architectural interior and the natural world outdoors. The focus here is on a permanent installation, Light Transport, which, at night, immerses the Zug train station in different colors, and the Skyspace Piz Uter in Zuoz--a plain, round structure made of stone, with a circular opening in its roof. These two works are used as examples of how Turrell's art unfolds, depending on whether it is in an urban or a natural space, and to show what sort of conclusions about his concept of art can be drawn from this. This extensive, carefully illustrated volume provides the viewer/reader with an experiential journey between the borders of seeing.