Prologue: Why study transport theory?

time-independent ("static") problems time-dependent ("dynamical") problems
microscopic use time-independent Schroedinger equation to obtain ground state, energy spectrum, etc. use time-dependent Schroedinger equation to describe scattering processes, dynamics of wave packets, etc.
macroscopic use equilibrium statistical mechanics to obtain the equation of state, properties at phase transitions, heat capacity, etc. need transport equations to describe irreversible processes, macroscopic currents, flows, diffusion, relaxation, dissipation, thermalization, etc.