Structure and evolution of central stars of planetary nebulae

We report on the present status of our knowledge concerning the structure and evolution of central stars of planetary nebulae. It is demonstrated how the whole evolution off the Asymptotic Giant Branch depends on the preceding mass-loss history. Mass loss determines not only the final mass but also the internal structure which controls the detailed evolution into a white dwarf configuration. However, since a theory of mass loss along the AGB is still lacking we have to rely on semi-empirical prescriptions, which do not allow to make precise predictions for the final evolution. In particular, the Wolf-Rayet central stars are still enigmatic objects and constitute a challenge for stellar evolution theory.