The theme of this book is an old one going back to the beginning of philosophy in Socrates' and Plato's encounters with the anti-rationalists of their day, the sophists. Though it cannot emulate the depth and subtlety with which these philosophers reclaimed rationality and knowledge from their detractors, in a nutshell the book investigates the following. Do knowledge and science arise from the application of canons of rationality and scientific method? Or is all our scientific knowledge caused by socio-political factors, or by our interests in the socio-political — the view of sociologists of "knowledge"? (As will be argued, the scare quotes are quite deliberately intended.) Or does it result from the interplay of relations of power — the view of Michel Foucault? Or does our knowledge arise from "the will to power" — the view of Nietzsche? It is argued here that, despite their large contemporary following, the latter fail badly to make their case against advocates of rationality and methodology in science and knowledge.