  We present a short overview of saturation physics followed by a summary of
the recent progress in our understanding of nonlinear small-$x$ evolution.
Topics include McLerran-Venugopalan model, Glauber-Mueller approximation,
nonlinear BK/JIMWLK evolution equations, along with the running-coupling and
NLO corrections to these equations. We conclude with selected topics in
saturation phenomenology.
