  In this lecture, we will survey the study of dynamics of the nonlinear wave
equation in recent years. We refer to some lecture notes including such as C.
Kenig \cite{Kenig01,Kenig02}, C. Kenig and F. Merle \cite{KM1} J. Shatah and M.
Struwe \cite{SS98}, and C. Sogge \cite{sogge:wave} etc. This lecture was
written for LIASFMA School and Workshop on Harmonic Analysis and Wave Equations
in Fudan universty.
