Among the most fascinating and rapidly developing areas in modem physics is the study of cosmological phenomena such as black holes, the cosmic microwave background, and the inflationary nature of the universe. Recent theoretical and experimental developments in these fields have significantly increased our understanding of these exciting and important topics. In order to allow the reader fully to understand these new developments, Quantum Theory, Black Holes and Inflation begins by introducing the theory of quantised fields in a mathematically rigorous fashion. Concentrating on the path integral approach to quantum field theory, the essential mathematical tools are developed to allow the reader to get to grips with the ways in which the theory has been successfully applied to a number of areas in modern cosmology. The second half of Quantum Theory, Black Holes and Inflation explains a number of the most successful applications to date, including the theory of black hole evaporation and thermodynamics, and the theory of quantum effects in the inflationary model of the universe. Quantum Theory, Black Holes and Inflation will be of great interest to all those involved in these vibrant areas of research. Its combination of mathematical background and the most successful modern applications of the theory make it accessible and interesting to both postgraduate students and more experienced researchers in the field.