This book describes, in clear terms, the Why, What and the How of Quantum Field Theory The raison d etre of QFT is explained by starting from the dynamics of a relativistic particle and demonstrating how it leads to the notion of quantum fields Non perturbative aspects and the Wilsonian interpretation of field theory are emphasized right from the start Several interesting topics such as the Schwinger effect, Davies Unruh effect, Casimir effect and spontaneous symmetry breaking introduce the reader to the elegance and breadth of applicability of field theoretical concepts Complementing the conceptual aspects, the book also develops all the relevant mathematical techniques in detail, leading e.g., to the computation of anomalous magnetic moment of the electron and the two loop renormalisation of the self interacting scalar field It contains nearly a hundred problems, of varying degrees of difficulty, making it suitable for both self study and classroom use. Everything OK great book Refreshingly different approach to QFT This book is a unique combination of mathematical rigor and conceptual insights Rather than taking the usual mundane route to QFT i.e classical fields canonical quantization interacting fields renormalization, this book first answers the fundamental question why fields This is done beautifully by evaluating the path integral for a relativistic particle and showing that interpretation of the resulting propagator in terms of objects known as fields is inevitable In my opinion, this is by far the best possible way to directly transition from a course in quantum mechanics to QFT Path integrals, Functional menthods and the Wilsonian interpretation of QFT are all emphasized from the start The highlight being all of these concepts made completely accessible at the master s early graduate level I wish I had access to such a book when I started with QFT Highly recommended