The varying organizational arrangements between firms 'networks' are a growing field of study for economics and sociologists. Whether described as strategic alliances, trading networks, joint ventures, or regarded as a product of industry structure or local conditions, they are seen as a form of economic co-ordination distinct from archetypal ideas of firms and markets. The purpose of this collectionwith contributions from European and American scholarsis to blend empirical research with conceptual discussion of networks under three main headings: Resource Flows, Mutual Expectations, and Information Flows. The contributors come from varying backgrounds: organization studies, economics, business history, marketing, and information systems. Together they are concerned with when, why, and how firms engage in inter-organizational networking, rather than relying on arms-length market relations or in-house procurement.