The Conference of Professors of Computer Science (CPCS), in conjunction with the British Computer Society, selects annually for publication a few of the best British PhD dissertations in computer science. Its aim is to make more visible the significant British contribution to this field, and to provide a model for future students. At most three or four dissertations are selected for publication each year. They have a high standard of exposition and place results particularly clearly in the context of computer science. Computer scientists with significantly different interests will be able to grasp the essentials of each book and use it as a means of entry to an unfamiliar research topic.