This thesis is divided into three sections. Section 1 provides the background and historical context for the study. Section 2 consists of four chapters presenting the research project and its findings, and Section 3 contains of two concluding chapters. This thesis considers the structure and organisational processes surrounding industrial design in manufacturing and service industries in Britain, and identifies and categorises the many decisions taken by managers that directly impact upon design development. The thesis differentiates between the acknowledged decision-making of designers and the unacknowledged decision-making of non-designers. These are called respectively "seen" and "silent" design, and the thesis concludes that design development is at its most effective when these processes act in tandem. Many organisations suffer from a corrupted process of design which at worst prevents new product development and at best slows and complicates it. In many cases this appears to be associated with a failure to give voice to the silent design activities of managers. The thesis uses primary data from representative case studies to trace the design process in organisations which can be shown to have used design "well" or "badly". The first step in this process is to understand the origins of any mistakes made in the categorisation of design. The second step is to recognise the way in which design, defined as a planning process to put ideas into action, has or has not been integral to new product development. The third step is to identify to what extent, at each stage of the process, there has been effective use of the deep knowledge vested in management and workforce. This deep, or "tacit" knowledge is also related to the idea of core competencies. The thesis suggests that utilisation of the deep knowledge in an organisation, changing it from passive to active, becomes sustainable as the two design processes are re-integrated in design development
