This book is of interest to researchers in astrophysics and the planetary sciences. It surveys the current knowledge on the propagation of nonlinear waves and the development of a turbulent dynamics in magnetohydrodynamic flows. The authors emphasize how the theoretical understanding of MHD waves and turbulence is related to the description of media where the presence of an ambient magnetic field is known to play an essential role. These effects are important in the physics of various space plasmas such as the magnetosphere, the solar wind, the solar corona, the interplanetary and interstellar media, etc. The authors treat fundamental aspects as revealed by asymptotic analysis, numerical simulations, and observations in the solar wind.