Plasma waves provide ample insights into the physical properties of plasma and have tremendous applications in space environment as well as in laboratories for industrial and scientific applications. Plasma being a intrinsically nonlinear medium, may lead to the formation of various types of localized coherent structures such as solitons, shocks, vortices, double layers etc. The nonlinear or turbulent state is often noticed in nature as well as in the laboratory. In the Earth's ionosphere, shock waves in space plasma, bow shocks near the heliosphere, nonlinear behavior in the fusion devices or microwave generating device, etc. It is, thus, important to have a knowledge on nonlinear coherent structures in plasma for the better understanding of the fourth state of matter, ``The Plasma"