In the promotion of urban sustainability in national and international arenas, numerous initiatives and programmes have been put into place to facilitate the creation and dissemination of`best practice' (1) through which to promote policy transfer and learning. However, despite the vast array of available best practices, little is known about the ways in which best practice is constructed, used, and contested, or of its implications for urban sustainability. In this paper I argue that, rather than consider the importance of best practice in terms of the extent to which it promotes the transfer of initiatives, or processes of lesson drawing, the creation, dissemination, and use of best practice can be better understood as a discursive process, in which not only is new knowledge created about a policy problem, but the nature and interpretation of the policy problem itself are challenged and reframed (Hajer, 1995;Owens and Cowell, 2002;Owens and Rayner, 1999). Drawing on insights from literatures on governmentality, I argue that best practice represents at once a political rationality and a governmental technology through which networks and coalitions seek to promote particular urban futures. However, in practice, the abstractions of best practice become enmeshed in the particularities of the places from which they are derived, and in political struggles over urban sustainability in the locales where best practice is deployed. Although such processes impede the translation and incorporation of local knowledges into political rationalities shaping the norms and rules of urban sustainability (Murdoch, 2000), they point to the