This book comprises material on color which was written by Wittgenstein in the last eighteen months of his life. It is one of the few documents which shows him concentratedly at work on a single philosophical issue. The principal theme is the features of different colors, of different kinds of color (metallic color, the colors of flames etc.) & of luminosity--a theme which he treats in such a way as to destroy the traditional idea that color is a simple & logically uniform kind of thing.