The analysis is developed stage by stage, with the emphasis on applicability and ease of comprehension, rather than on generality or mathematical elegance. Financial performance, the second-best, the optimal degree of complexity of price structures and problems of optimal quality are first discussed in a static framework. Time is next introduced, leading to a marginal cost concept derived from a multi-period optimizing model. The analysis is then related to urban transport, shipping, gas and coal. This is likely to become a standard work of more general scope than the authors earlier book on electricity supply. It rests, however, on a similar combination of economic theory and high-level experience of the real problems of public enterprises.