Book excerpt: A short account of the philosophy of knowledge for students reading philosophy for the first time. It also serves as a general introduction to those interested in the subject. Jennifer Trusted examines the nature of philosophy as a subject for study and suggests that it has practical use as well as intellectual appeal since it is concerned with developing our understanding through critical appraisal of the concepts we use, so making our problems clear. Dr Trusted also looks at the approach of some of the leading philosophers of the western world to the philosophy of knowledge. The views of Plato, Aristotle, Descartes, Locke, Berkeley, Hume and Kant are considered. There are two chapters principally concerned with the views of the twentieth-century philosophers: A.J. Ayer and Norman Malcolm. The concluding chapter summarises the various approaches and the way they contribute to clarifying our ideas.