ABSTRACT
In this chapter we give a brief but sufficiently complete review of the technical tools of quantum field theory. The use of the term “quantum” is traditional: the techniques described below were first developed for quantum (pseudoEuclidean) field theory. However, the techniques themselves are not related at all to quantum physics, and can equally well be applied to the theory of a classical random field, in particular, the fluctuation theory of critical behavior. The term “operator” in quantum field theory corresponds to the term “random quantity” in the problems we shall discuss.
