This book is the first attempt for a systematic study of infinite dimensional dynamical systems generated by dissipative evolution partial differential equations arising in mechanics and physics, along with other areas of science and technology. A synthetic view of the relation between infinite and finite dimensional systems is presented. Equations considered include reaction-diffusion, Navier-Stokes and other fluid mechanics equations, magnetohydrodynamics, thermohydraulics, pattern formation, Ginzburg-Landau and damped wave. The last chapter of the book introduces inertial manifolds, a subject of rapid development.