This is a companion volume to a series of four books about 20th century art. Each book can be read independently and is accessible to the general reader. However, as a series they form the main texts of an Open University third-level course, "Art of the Twentieth Century", which examines the fundamental changes that have taken place in the concepts of art during the 20th century. The "Course Reader" consists principally of writings by art historians and art theorists, originally published as free-standing essays or chapters in books, and gives readers access to a wide range of different authorial voices and perspectives on art beyond those explored in the four accompanying course texts. Drawing on material relating to the rest of the course, the book reflects the diversity of art-historical interpretations and of different theoretical approaches to 20th century art.