research are subject to peer review but, in most cases, the reviewers will be drawn from cognate or related fields. This is particularly common in research funding decisions, where the likelihood of an application being reviewed by non-specialists increases with the amount of money involved. Even in the case of smaller awards, and of peer reviewed papers, it is still often the case that reviewers will have contributory expertise in a different narrowly defined specialism to that of the author being reviewed. If interactional expertise did not exist, then justifying peer review would be difficult. If, however, reviewers can have expertise by virtue of their interaction with a range of cognate scientists, then the process of peer review seems reasonable. The management of large organisations Whilst there may be some skills that are more or less generic in the management of large organisations – presumably the kinds of skills that are taught on MBA schemes around the world – we can also ask if managers do better if they understand particularities of the business they are in charge of. Intuitively it seems reasonable to suggest that the manager of a newspaper should know something about how a journalist works or that a manager of a car factory should know something about how a production line works. Whilst this kind of thinking is formally included in many training schemes, the idea of interactional expertise allows us to ask about the kind of experience that is needed in order for managers who lack the embodied experience of writing copy or working on a production line to understand what this is like for those that do fulfil these roles. One implication of interactional expertise is that direct experience – working one’s way up through the ranks – may be less important than previously thought even though lots of interaction with those who do these tasks could still be important. Certainly in the management of large science projects, managers will work hard to acquire interactional expertise quickly. Interdisciplinary trading zones In art, design, science, technology, medicine and public policy many activities are undertaken by interdisciplinary teams. In science and technology, these take the form of scientists and engineers from many different disciplines working together on a single project. It is this situation, in which different groups of specialists with different, mutually incompatible and sometimes incomprehensible ideas nonetheless manage to find a way of communicating