This graduate-level introduction to the theory and applications of time correlation functions and the molecular theory of fluid dynamics provides experimentalists with the theoretical tools useful for analysis of experimental results, and theoreticians a comprehensive source of illustrations of theories most relevant in practical applications. The book reviews the concepts, basic tools and basic approximations of molecular hydrodynamics, then explores self-diffusion, space-dependent diffusion, hydrodynamic fluctuations, fluctuations at finite wavelengths and finite frequencies. 110 illustrations.