This book provides a historical overview of philosophical debates about the distinction between science and pseudo-science, and a demonstration of how the Western Marxist tradition’s notion of the critique of ideology can elucidate this distinction. The way in which pseudo-science is often ideologically motivated is discussed in depth. Particular attention is paid to the manner in which ideology masquerading as science manifests itself in the work of genuine scientists themselves, when they popularize their work or interpret the social significance of their findings. The question of the demarcation between science and pseudo-science was once a central theme of the philosophy of science, with Karl Popper’s criterion of ‘falsifiability’ (the capacity of a hypothesis to be refuted by evidence) drawing heated debate. The author furthers the case for the centrality of the question of demarcation to a critically confident philosophy of science and argues for the value of incorporating ideology-critique into this field. This unique approach makes the book of great value to  anyone interested in the history and philosophy of science and anyone interested in the social and political context of scientific research.