  This chapter is a non-expert introduction to the effective field theory of
large scale structure. First, we give a detailed pedagogical explanation of why
previous attempts to build non-linear cosmological perturbation theory failed.
After that we introduce the description of dark matter as an effective
non-ideal fluid and show how it corrects the shortcomings of the previous
approaches. Finally, we develop a formulation of the effective field theory of
large-scale structure from a nonequilibrium field theory perspective, called
time-sliced perturbation theory. We show how this framework can be used for a
consistent renormalization of cosmological correlation functions and a
systematic resummation of large infrared effects relevant for the baryon
acoustic oscillations.
