This collection of eleven essays is to honour Barry Barnes both on his retirement from the University of Exeter and on forty years' association with the Edinburgh Science Studies Unit. The generative quality of Barnes's work is exemplified beautifully in the temporal and geographical spread of the contributors, many of whom were at some stage members of the by-now legendary Edinburgh unit; or if they were not, are first- or second-generation comrades-in-arms in the broadly conceived sociology of scientific knowledge (SSK) agenda.

Mazzotti's introductory essay offers a helpful short overview of the emergence and growth in the early 1970s of this agenda, with its novel view of knowledge in general and scientific knowledge in particular. Mazzotti describes Barnes's central role in these developments, providing a summary of the corpus of his work and pointing out the intellectual resources he drew upon – along the way providing a genealogical mapping of the field. Although Marx has his place in the account, it is disconcerting to note that none of the other influential Marxist historian–sociologists of science – one thinks of Franz Borkenau, Henryk Grossman, Boris Hessen and Edgar Zilsel – are mentioned. Following this historical opener we encounter a set of contemporary explications and elaborations, featuring David Bloor and Trevor Pinch on the meaning and role of methodological relativism (a principal tenet within SSK), and a concise exercise in scathing irony by Harry Collins. Under the cloak of a discussion of hoaxes, Collins takes on the science wars, and the intentions and objectivity of authors, by way of imaginative historical and philosophical applications and extrapolations of – and variations on – Barnes's continuously evolving work.

Although the volume is not formally divided into sections, the next three essays, by Steven Shapin, Karin Knorr-Cetina and Donald MacKenzie, form a fairly coherent cluster. Shapin, who has been working in recent years on the changing character of academic and industrial science in the USA since the 1970s, contributes a deeply absorbing study of the prehistory of these changes (from 1900 to 1970). His focus is scientists' commitment, or lack thereof, to a ‘scientific’ ethos at various levels of academic institutions and industrial enterprises. Knorr-Cetina's article continues her evolving work on the notions of ‘practice’ and ‘object’. One can look upon it as an exploration of Barnes's sociality. The main thrust of her essay is to posit a relational–affective mode of doing science, founded on two interwoven distinctions: between practice as ‘performative’ research routine and practice as a ‘relational’, dynamic process, disruptive and potentially innovative; and between objects in our everyday acquaintance and ‘knowledge objects’ or ‘epistemic (nonhuman) objects, distinguished by their multilevelled incompleteness, partiality or indefinite unfolding. MacKenzie elaborates on Barnes's and Bloor's notion of ‘finitism’, and on Barnes's related interest in rule-following and in habits of classification, in order to elucidate the production of financial reports, looking in particular at bookkeeping practices that combine automated and non-automated elements. In a case study of a medium-sized British firm attempting to make its way between UK and EU accounting regulations, MacKenzie shows how useful the finitist viewpoint is in trying to understand accounting as the contingent classification of particulars, and so as a practice dependent on human context and circumstances.

The final cluster of essays, by Mark Haugaard, Martin Kusch and Steven Loyal, revolves around notions of power and agency as expounded by Barnes and expressed in the complex interplay between individuals and collectivities. All three essays bring out the significance of the collectivity for Barnes (who cites Durkheim as one of his intellectual sources), his sharp criticism of individualist positions in current sociology, and his effort to present what he has termed a ‘monist’ and ‘naturalist’ social point of view. Drawing on Barnes's On the Nature of Power (Cambridge, 1988), Haugaard offers an analysis of the concept of power, distinguishing between legitimate and illegitimate varieties. But he removes Barnes's conception of power as capacity for action from the methodological plane and locates it instead on a normative one, deploying Barnes's construction of social knowledge through social rings of reference, and injecting normativity into his notion of a social agent. Kusch offers a brilliantly crystalline and sophisticated philosophical critique of the analysis of the ‘free will’, or voluntaristic, discourse in Barnes's later book Understanding Agency: Social Theory and Responsible Action (London, 2000). Kusch applauds Barnes's relating of the discussion of responsibility, agency and free will to collectivist sociality rather than to individualized discreteness, but calls him to task for not taking sufficient notice of philosophical discussions of free will and related topics, such as the significant use of intuition versus empirical observation in formulating moral theories, and the meaning of legal practices and formulations. Another variation on these themes is offered in Loyal's essay, which applies this same book's conceptual framework in a discussion of the status and predicament of asylum seekers in Ireland. He views Barnes's ideas as a fruitful way to escape the apparent need to choose between utility-based microcausal explanations of the situations of migrants and refugees and historical–structural macrocausal explanations. Loyal elaborates in particular Barnes's notion of statuses, accountability and susceptibility, seeing in these valuable tools for analysing actual case studies and the role in them of agency and responsibility.

The last essay, by John Dupré, consists of a sharp critique of evolutionary psychology through a succinct but intricate summary of the state of the art in present-day biological research on evolutionary and intergenerational transfer conceptions and mechanisms. It is related to the above cluster by his rejection of the highly discrete and individualized gene-centred view of heredity adopted by evolutionary psychology. This view is contrasted with the emphases on developmental systems, nongenic hereditary mechanisms, environments and multilevel dynamic interactions offered by recent biology.

Knowledge as Social Order is a valuable, though not evenly interesting, volume. It gives readers an acute sense of why discussions of sociality, social constructivism at large, and Barnes's work within it, have created a body of work that keeps on growing and is still relevant.