Against Method is a classic and notorious book. This fourth edition is introduced by Ian Hacking, who opens with a useful point about our interpretation of it. This is that Feyerabend wrote the book at a time of considerable tumult in both the philosophy of science and wider society. The clashes between Popper, Kuhn and Lakatos were transforming our understanding of science against a backdrop of social and political ferment. Feyerabend clearly revelled in social and intellectual dramatics and Against Method, across all its four editions, reflects this: his aim is to provoke his readers into challenging their preconceived ideas about science, its history, its philosophy, and its significance. The real intellectual core of the book is expressed neatly in Chapter 19 in three curt questions: what is science? What is so great about science? And how are we to use the sciences and who decides the matter?

These three questions arguably sit at the centre of Feyerabend's work in the history and philosophy of science. Against Method should therefore be judged in terms of its success in provoking us to ask them, or at least to take them seriously. Feyerabend was an enthusiast for the sciences, but was never able to embrace them uncritically. He insisted that an understanding of the nature and value of science will depend upon both historical and philosophical inquiries. Responding to a positivist climate which is now largely passed, Feyerabend insisted that the sciences had to be understood within their social and intellectual contexts. Science and scientists are not free-floating entities, disconnected from the trends and concerns of the wider world. Many philosophers of science of the 1960s and 1970s did not take kindly to Feyerabend's emphasis on the grubby, all-too-human nature of science, replete with polemics, scandal, rhetoric, politicking and the like.

The core thesis of Against Method is as simple as it is striking. There is no singular, formalized set of ahistorical and context-insensitive scientific methods. Instead, argued Feyerabend, scientific practice is complex and particularistic. It relies upon an often unstable interaction of formal and informal methodologies, contingent social and material conditions, and a host of implicit and explicit intellectual conditions. This philosophical claim is illustrated with a long case study of Galileo. Feyerabend insisted that science is tied to multiple material, social and intellectual conditions which enable and render intelligible certain forms of scientific inquiry at the same time as they obscure others.

The obvious remedy to this is an emphasis upon scientific and historiographical pluralism – many ways of doing science and of understanding its history. Feyerabend emphasized the ‘human’ dimension of scientific research and explored the ways in which the contingencies thus introduced should affect our judgements about the epistemic authority of scientific knowledge. He always sought to connect and illustrate abstract philosophical concerns with rich historical examples and thought that each was impoverished without the other. Contemporary interest amongst historians and philosophers of science in values, pluralism, and contingency owes a lot to Feyerabend's early challenges to positivist models of science.

History, of course, has not been wholly kind to Feyerabend. Today, he enjoys (or suffers) a reputation as an iconoclast, a cultural relativist, an enthusiast for voodoo and astrology, and the like. Much of this bad reputation is due to his rhetorical excesses and occasional intellectual sloppiness. This fourth edition, for instance, preserves the claim that science is simply one epistemic tradition amongst others (Chapter 18) and repeats the notorious call for the separation of science from the state (Chapter 19).

Such remarks may excite and frustrate us, but few take them seriously – and with good reason. But Feyerabend should not be judged guilty as charged. His initial motivation for making such outrageous claims was, as he cheerfully admits, to shock and upset staid philosophers of science, rather than to indicate his enthusiasm for them. A careful reading of Feyerabend's later writings in the 1980s and 1990s indicates a growing hostility to relativism and a consistent, if grudging, admiration for the epistemic achievements of the modern sciences. For sure, Feyerabend too often succumbs to rhetoric and polemic, but, so he thinks, with good cause: motivating people to ask the questions of what science is and what is so great about it are, to his mind, far more important than boring conformity to scholarly decorum. This explains why the book features references to Dadaism, Christian mysticism, the Homeric epics, Lenin and Brecht.

Feyerabend once remarked that he ‘wrote essays which upset people’, quickly adding that such upset was – in most cases – wholly justified. Certainly the project of generating a sustained critical inquiry into the cognitive and cultural authority of the sciences justifies our upsetting a few scholars along the way. For all his shortfalls, Feyerabend succeeds wonderfully in challenging triumphalist narratives of science and in provoking us to take seriously the foundational questions of how and why the sciences came to enjoy such a central and privileged place within Western modernity.

This edition includes a ‘Letter to the reader’, presumably intended for inclusion in Feyerabend's last book, Conquest of Abundance (1999), but whose content is applicable to Against Method. Addressing his reader directly and without the usual polemics, Feyerabend explains that his aim is not to inform or to establish truths, but rather to change his readers’ attitudes. As a patient, documentary study in the history and philosophy of science, Against Method is often, but not always, flawed; however, to judge it thus would be to misunderstand its purpose. Feyerabend's Against Method is intended to emphasize the urgency of our gaining a proper historical and philosophical understanding of science. Anyone who worries about or forgets why science, its history and its philosophy matter should consult this book. Its capacity to provoke, confound and delight is not a fault, but its great virtue.