Abstract These papers report untold and unfashionable stories in the history of technology. They focus on practical developments rather than science. Two papers (Stretch, Blue Danube) concentrate on practical issues of manufacture, maintenance and use. They show how solutions to technical problems emerge over time, often in unforeseen ways. Along with the paper on missile guidance systems, they highlight the impetus given by problem solving in the face of bottlenecks and âreverse salientsâ that obstruct progress on a technology. Innovation can be seen as a process of creative engineering to resolve a set of âproblem sequences.â One paper on construction (Shotton) highlights the dilemmas faced when adopting technology from outside the firm: who should supply the new technology and what scale of plant should be built? Another paper (Open versus closed innovation) considers the best form of organisation suited to developing innovations in house. Here too, cooperation with partners turns out to be the best way forward. The paper on process control shows how mobility of technical labour and a strong product champion encouraged the spread of a rapidly evolving computer technology throughout South Wales. These papers are almost entirely based on primary sources, including company archives, oral history interviews, technical publications and correspondence with the innovators themselves. The strengths and shortcomings of this approach are explored, particularly in the defence sector. This approach of âhistory from belowâ is born of a conviction that even headline stories (such as the UK atom bomb) overlook the mundane nature of conventional engineering. In the case of atomic weapons, science was the heroic story - a myth which is still current. These papers show how technology actually develops and explore hitherto undocumented fields of technology. All of these papers show how knowledge coalesces from diverse sources to generate innovations in an evolutionary way. Even a top secret project like the atomic bomb draws know-how from a wide range of suppliers. The papers focus on the way in which this diverse knowledge comes to be incorporated in new technologies. Evolution is a broad analogy. Most technologies evolve through purposive selection rather than random chance exhibited by the natural world of living beings. History matters when technology is being developed. Firms accumulate expertise and learn within networks and generate a variety of solutions to a given problem. Reverse salients often produce radical changes or mutations in technology. A selection process operates at all levels to identify satisfactory solutions which work. This is not necessarily optimal and organisations may get locked in to a particular technology as it develops in a path dependent way. The dynamics of innovation may be unforeseen in advance, but they can be traced in retrospect. These case studies also offer lessons in the way technical development might be organised. Loose âcommunities of practiceâ drawing upon a range of skills and experience are often ideal at the development stage. Formal management is more appropriate to the production phase. Guided missile control at Wythenshawe developed in just such a loose way. Secrecy rules inhibited similar cooperation over the atomic bomb, but individuals were given remarkable freedom. The case of computer control highlights the role of product champions driving innovation at a senior level. Surprisingly, careful use of resources does not seem to inhibit innovation. Shotton, the atomic bomb and the wide strip mill were all developed in an atmosphere of parsimony.