Summaries This article draws on research in Tanzania to explore the socially embedded nature of institutions for common property resource management and collective action. The article challenges the design principles common in resource management literature and explores instead the idea of ‘institutional bricolage’ ? a process by which people consciously and unconsciously draw on existing social and cultural arrangements to shape institutions in response to changing situations. The resulting institutions are a mix of ‘modern’ and ‘traditional’, ‘formal’ and ‘informal’. Three aspects of institutional bricolage are elaborated here: the multiple identities of the bricoleurs, the frequency of cross?cultural borrowing and of multi?purpose institutions, and the prevalence of arrangements and social norms which foster cooperation, respect and non?direct reciprocity over life courses.