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Wee felt it before in sense; but now wee know it by science. Edward Misselden (1623) The collective effort reported in this volume is the outcome of the diffusion of the idea of diffusion as a fundamental process in society. The considerable number of disciplines represented here indicates the weight of the problem area. The editors are to be congratulated for their initiative in drawing together present thinking at a vivid meeting, now also in print. An old timer in the business has not much to add. But maybe some things, bearing in mind that a Preface is a celebration and not a review. As always with ideas it is hard to identify those who first gave shape to the idea of diffusion. In a general sense it is probably an observation as old as human self-reflection that groups of populations exchange ideas and copy habits and implements from each other. Sometimes it has even been recommended, as a Chinese proverb suggested millenia ago, "If you want to become a good farmer, look at your neighbor" .

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1 Rat Race Dynamics and Crazy Companies: The Diffusion of Technologies and Social Behavior.- 2 Democratization from a Long-term Perspective.- 3 Innovation and Diffusion in a Single Europe: Institutional Structure and Industrial Prospects for the European Communities.- 4 Multiple Perspectives on Technological Diffusion: Insights and Lessons.- 5 Technogenesis: Origins and Diffusion in a Turbulent Environment.- 6 New Product Diffusion Models in Marketing: A Review and Directions for Research.- 7 The Research on Innovation Diffusion: An Assessment.- 8 Adoption and Diffusion of Technology as a Collective Evolutionary Process.- 9 Diffusion of Innovations Under Conditions of Uncertainty: A Stochastic Approach.- 10 Temporal Diffusion and Population Dynamics: A Systems Model.- 11 Diffusion Through Interfirm Cooperation: A Case Study.- 12 Some General Regularities of Techno-Economic Evolution.- 13 The Adoption of Applications of Information Technology for Process Development: A Regional Case Study.- 14 External Learning Opportunities and the Diffusion of Process Innovations to Small Firms: The Case of Programmable Automation.- 15 Material Substitution: The Role of New Technology.- 16 Morphological Analysis, Diffusion, and Patterns of Technological Evolution: Ferrous Casting in France and the FRG.- 17 Competition and Complementarity in Diffusion: The Case of Octane.- 18 Diffusion: Long-term Patterns and Discontinuities.- 19 Diffusion of Pervasive Systems: A Case of Transport Infrastructures.- 20 Determining the Service Life Cycle of Computers.- 21 Diffusion of Process Technology in Dutch Banking.- 22 The Chain Saw in Swedish Forestry.- 23 The Spatial Spread of the Aids Epidemic in Ohio: Data Analyses via Expanded Regressions.- 24 Branching out into the Universe.- List of Contributors.- Conference Program.- List of Participants.

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