This book offers a vigorous and constructive challenge to the various forms of anti-realist and cultural-relativist thinking. By examining a wide range of anti-realist theories, the author is able to highlight the problems, including the ethical dilemmas, to which they give rise, and in response offer a variety of arguments amounting to a strong defence of critical realism in the natural and social sciences. These arguments are drawn from a wide range of sources such as theoretical physics, philosophical semantics, deconstruction and critical theory. This book will thus be of interest to both students and scholars in the fields of critical theory, philosophy and history of science, and epistemology, demonstrating as it does the incoherence of anti-realist doctrines.