Concerning the Spiritual in Art is a 1913 book by the Russian abstract painter Wassily Kandinsky. Kandinsky claims that artists lead mankind from a lower to a higher spiritual state throughout history, despite temporary decadent setbacks. Kandinsky describes the principle of "inner necessity" by which color and form resonates with the human soul. Kandinsky spends much of the book describing the symbolic and spiritual qualities of different colors and their combinations. For example: yellow as warm and terrestrial, blue as cold and celestial, black as death.
Boasting the largest collection of book summaries, BookRags is the best option for titles you can't find elsewhere. They offer all of the basics (quotes, chapter summary, characters, historical context, literary criticism) but also walk through a few major topics that recur throughout the book, which can be particularly useful for essay writing.