Richard Wollheim's (1923-2003) was the leading voice in the philosophy of art in the Anglo-American tradition during the second half of the twentieth century. This volume serves two purposes. First, at the time of his death, Wollheim was composing a short book, comprising two lectures first delivered, respectively, at Barcelona and at Lawrence, Kansas--versions of which appeared in 1994 ('On Formalism and Its Kinds') and 2001 ('On Formalism and Pictorial Organisation')--plus substantial new material. The whole text is reproduced here for the first time. The material offers new considerations in favour of his psychological conception of pictorial art as against the semiotic conception, arguments for the inadequacy of formalism, and close and compelling analyses of pictures by Ruisdael, Monet, and others, using in novel ways his well-known ideas in pictorial aesthetics to arrive at a theory of pictorial organisation. Second, although Wollheim was well-served by various collections of his work to 1994, at that point some important articles and reviews had yet to be selected for republication--in some cases available only in locations difficult to access--as well as his having published further work after 1994. The present volume fills both gaps: it thus provides the final pieces for a complete collection of Wollheim's works in the philosophy of art. This is one of three planned volumes of Wollheim's previously uncollected work for Oxford University Press. The others are Writing on Political Philosophy, edited by Jonathan Wolff; and Writing on Philosophy and the Mind, edited by Garry Hagberg.