Travelling waves are observed in many natural processes, ranging from the spread of diseases to the combustion of fuels. The book is concerned with characterizing such waves in phenomena described by a nonlinear diffusion-convection-reaction equation. The technique employed is new and can be briefly described as an integral or integrated approach to phase-plane analysis. It leads to results which were so far unobtainable, including the effects of degenerate diffusion and nonlinear convection, or are much sharper than those obtained previously. Applications are taken from the evolution of biological populations, diffusion of oxygen in tissue, heat transfer, thermal convection, combustion, flow in porous media, hydrology, soil-moisture flow, boundary layer theory, foam drainage, viscous fluid flow, turbulent fluid flow, the motion of plasma particles in a magnetic field, solar prominences, crystal growth, reaction chemistry, quenching, and other fields. In this way, the book brings together and improves a large number of results which have been obtained piecemeal in many different scientific disciplines. It provides a reference work for applications of nonlinear diffusion, convection and reaction, and gives a state-of-the-art survey of the study of the occurrence of travelling waves in such applications.