  In recent years we have witnessed a growing interest in various
non-equilibrium systems described in terms of stochastic non-linear field
theories. In some of those systems like the KPZ and related models, the
interesting behavior is in the strong coupling regime, which is inaccessible by
traditional perturbative treatments such as dynamical renormalization group
(DRG). A useful tool in the study of such system is the Self Consistent
Expansion (SCE), which might be said to generate its own "small parameter" .The
self consistent expansion (SCE) has the advantage that its structure is just
that of a regular expansion, the only difference is that the simple system
around which the expansion is performed is adjustable. The purpose of the this
article is to present the method in a simple and understandable way, that
hopefully will make it accessible to a wider public working on non-equilibrium
statistical physics.
