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 collection — with contributions from European and American scholars — is 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.