'… a very well written book which covers thoroughly various formalisms for studying nonequilibrium statistical mechanics and nonequilibrium.quantum field theory … The authors have written many of the seminal papers and the book is a masterpiece of pedagogy, explaining and resolving very clearly many of the technical issues that had to be overcome in the development of this subject. It should prove essential reading to anyone venturing to work in this important new field.' Fred Cooper, Program Director of Theoretical Physics, National Science Foundation