Book excerpt: This is a basic book on the theory of color mixing -- but it's not your ordinary color theory book by any means. This one comes from Helen Van Wyk, recognized by her many thousands of fans and by her contemporaries as the quintessential expert on color mixing. She explains color mixing clearly so that oil and acrylic painters will learn how to put color theory into action. They'll see how they can paint any subject with the six basic colors plus white and gray.