This book develops quantum field theory in curved spacetime in a pedagogical style, suitable for graduate students. The authors present detailed, physically motivated, derivations of cosmological and black hole processes in which curved spacetime plays a key role. They explain how such processes in the rapidly expanding early universe leave observable consequences today, and how in the context of evaporating black holes, these processes uncover deep connections between gravitation and elementary particles. The authors also lucidly describe many other aspects of free and interacting quantized fields in curved spacetime.
One of the best book on the topic, covers everything in the pedagogical order. Covers almost everything but just lacks in the segment where it couldn't argue why exactly is it that, the definition of particle is ambiguous in curved spacetime, apart from that everything else is here. I wanted a single source, where I could everything that was relevant to this field, so that perhaps in the future i would be able to understand the research done in this area.