Paul Klee was a Swiss-born German artist. His highly individual style was influenced by movements in art that included expressionism, cubism, and surrealism. Klee was a natural draftsman who experimented with and eventually deeply explored color theory, writing about it extensively; his lectures Writings on Form and Design Theory, published in English as the Paul Klee Notebooks, are held to be as important for modern art as Leonardo da Vinci's A Treatise on Painting was for the Renaissance. He...