Phenomenalism is a philosophical theory of perception involving the idea that statements about material objects can be explained in terms of statements about actual and possible sense experiences. In this study James Giles explores the development of phenomenalism through the works of Locke, Berkeley, Hume, and others. He shows how problems occur for phenomenalists precisely at the point where they abandon their empiricism. Holding to empiricism, Giles then presents his own version of phenomenalism as a metaphysical thesis in which the material objects are constructed out of sense experience. He then argues that the major critiques of phenomenalism, including Wittgenstein’s private language argument and Sellars’ famous attack on the ‘myth of the given’, all fail to dislodge the basic phenomenalist insights.