... a legacy the author is leaving to those interested in understanding quantum field theory at the deepest level. (G. Veneziano, CERN, Geneva)... of significant interest to researchers in quantum field theory and quantum gravity, particularly in the general relativity community. (R. Wald, University of Chicago)The book's presentation is very impressive. Conceptual problems are elegantly exhibited and there is an inner coherent logic of exposition that could only come from someone who had long and deeply reflected on the subject, and made important contributions to it. (Luis Alvarez-Gaume, CERN Courier)This book is one of the best books dealing with quantum field theory existing today. It will be of great interest for graduate and postgraduate students as well as workers in the domains of quantum field theory in flat and in curved spacetime and string theories ... share the deep and unique vision of the quantum theory of fields and its formalism by one of its greatest expositors. (Journal of Physics)... should be particularly useful for quantum field theorists (especially students), theoretical physicists and mathematicians with an interest in physics. (CERN Courier)Over the past five decades, DeWitt has worked on the gamut of formal ideas in QFT. 'The Global Approach to Quantum Field Theory' crystallizes a pioneer's view of the subject's development during those years. (Stanley Deser, Physics Today, March 2004)