This, the second volume in this series, consists of five chapters. The first
chapter, written by Bertand Delamotte, serves as an introduction to the
non-perturbative renormalization group. In a traditional survey, an application
of a renormalization group (RG) formalismin the quantitative theory of
critical phenomena originates from two seminal papers by Kenneth Wilsonb
relying on Kadanoff-Wilson coarse graining ideas which do not assume per
se any perturbation expansion. However, in 1970-80s – the most advanced
period for the application of the method – the term ’renormalization group’
was used nearly synonymously with the perturbative field theoretical RG.