The book concerns the study of positron-acoustic waves (PAWs) in an unmagnetized, collisionless, dense plasma system consisting of cold positrons, degenerate electron and hot positron fluids and positively charged static ions. The well-known reductive perturbation method is employed to derive the Korteweg-de Vries (K-dV), modified K-dV (mK-dV) and Burgers equations. The basic properties of PAWs (viz. amplitude, width, and phase speed) are incomparably influenced by the effects of degenerate pressure, kinematic viscosity, planar and nonplanar geometries, and plasma particle number densities. For the non-relativistic limits in like manner for the ultra-relativistic limits, the nonlinear waves (viz. solitary and shock) are modified significantly. The relevance of the results in some astrophysical compact objects including non-rotating white dwarfs, neutron stars, etc. are extensively specified in this book.