Almost one hundred years ago, artists began eliminating the familiar visible world from their paintings. Abstraction enabled artists to embody their ideas in paintings, many of which concerned the spiritual, including references to popular belief systems such as Theosophy and Rosicrucianism. Yet as the 20th-century progressed, those unfashionable beliefs were ignored as art criticism focused on the way a painting looked rather than what an artist had intended it to mean. Much was lost as a result, and it is this missing content that "The Spiritual in Art" aims to restore. This book, now available in paperback, challenges current assumptions about abstraction, from the Symbolism that prefigured abstract art to the current manifestations of spiritual content in American and European painting. Special attention is paid to the pioneers of non-representational art - Wassily Kandinsky, Frantisek Kupka, Kazimir Malevich, Piet Mondrian - and to other masters, such as Jean Arp and Jackson Pollock, whose connections with the spiritual have been largely overlooked. This presentation of new and rediscovered ideas should have an impact on art scholarship.