Herschel B. Chipp's 'Theories of Modern Art: A Source Book By Artists and Critics' is a collection of texts from letters, manifestos, notes and interviews. Sources include, as the title says, artists and critics - some expected, like van Gogh, Gauguin, Apollinaire, Mondrian, Greenberg, just to name a few - and some less so: Trotsky and Hitler, in the section on Art and Politics. The book is a wonderful resource and insight into the way artists think and work.