In this book, our aim is to study well-posedness and decay rates of the compressible Euler equations with damping and related model. It is known that Euler equations is one of the most important equations in Fluid Mechanics and gas dynamics. The closely related model such as quasilinear hyperbolic equations with nonlinear damping is also studied. This book consists of two parts. Part 1 is to study the global existence and decay rates of the 3D compressible Euler equations with damping. Part 2 is to study the global existence and decay rates of the 3D quasilinear hyperbolic equations with nonlinear damping.