The book investigates two important subjects simultaneously. On the one hand, it is concerned with the detailed processes which have lead to quite different innovation diffusion pathways of combined heat and power technology in the UK and Germany since the early Eighties. On the other hand, this empirical work serves to demonstrate the application of a novel multi-disciplinary and prospective research approach. This approach, which is explicitly formulated in both theoretical and methodological terms, is used to explore the possibilities and limitations of controlling the transformation of large socio-technical systems by poltical means.