First released in 1901, this Theosophical book assserted that thoughts could be 'seen' by those with the right perceptive abilities. It then went on to show what auras looked like, illustrating them in full colour. Central to the book are 58 illustrations of Annie Besant's and Charles Leadbeater's friends' clairvoyant observations of the 'thought forms' of music, emotions and experiences. In addition, it provided a colour chart for the clairvoyant.
The book is highly important because it had a profound influence on the development of abstract art in the early twentieth-century art: Wassily Kandinsky, Hilma af Klint, Piet Mondrian, and Paul Klee. This updated edition, a beautiful hardback, it features colour corrected full-colour illustrations and a new introduction by Mitch Horowitz. A short Youtube on it is HERE.