Lectures given at the 3rd 1982 Session of the Centro Internazionale Matematico Estivo (C.I.M.E.). Held at Varenna, Italy, August 22 - September 1, 1982
§ 1. Introduction and motivation.- Smooth solutions for the equations of compressible and incompressible fluid flow.- The linear transport operator of fluid dynamics.- Limites des equations d’un fluide compressible lorsque la compressibilite tend vers zero.- Vortex theory and euler and navier-stokes evolution in two dimensions.- Free boundary problems for compressible viscous fluids.