This paper traces the main lines of evolution of the organization of professional work. The argument is illustrated with material on the case of doctors and hospitals. While market and hierarchy principles have become progressively more salient in professional work, we argue that, in parallel, the community principle has been growing more influential, too. We further argue that professional community is mutating from a Gemeinschaft, craft guild form, via Gesellschaft forms, toward a new, collaborative form. This evolution, however, is a difficult one, and the outcome is uncertain. We identify some implications for future research.

Solidarity has long been considered essential to labour, but many fear that it has declined. There has been relatively little scholarly investigation of it because of both theoretical and empirical difficulties. This article argues that solidarity has not declined but has changed in form, which has an impact on what kinds of mobilization are effective. We first develop a theory of solidarity general enough to compare different forms. We then trace the evolution of solidarity through craft and industrial versions, to the emergence of collaborative solidarity from the increasingly fluid ‘friending’ relations of recent decades. Finally, we examine the question of whether these new solidarities can be mobilized into effective collective action, and suggest mechanisms, rather different from traditional union mobilizations, that have shown some power in drawing on friending relations: the development of member platforms, the use of purposive campaigns and the co‐ordination of ‘swarming’ actions. In the best cases, these can create collective actions that make a virtue of diversity, openness and participative engagement, by co‐ordinating groups with different foci and skills.

In recent decades, alternative organizations and movements -'quasi-unions'- have emerged to fill gaps in the US system of representation caused by union decline. We examine the record of quasi-unions and find that although they have sometimes helped workers who lack other means of representation, they have significant limitations and are unlikely to replace unions as the primary means of representation. But networks, consisting of sets of diverse actors including unions and quasi-unions, are more promising. They have already shown power in specific campaigns, but they have yet to do so for more sustained strategies. By looking at analogous cases, we identify institutional bases for sustained networks, including shared information platforms, behavioural norms, common mission and governance mechanisms that go well beyond what now exists in labour alliances and campaigns. There are substantial resistances to these network institutions because of the history of fragmentation and autonomy among both unions and quasi-unions; yet we also identify positive potential for network formation. Copyright Blackwell Publishing Ltd/London School of Economics 2006.