Centaurus A: A Multifrequency Review

Due to its peculiar appearance in the optical, its proximity, and its importance for the understanding of active galaxies and their active galactic nuclei (AGN), Centaurus A has been observed frequently within the last 150 years in all accessible wavelength bands. Thus a wealth of data exist over a wide range in frequencies (wavelengths, energies), which have been compiled in the ``NASA Extragalactic Database" (NED). A multifrequency combination of all those results allows to establish the important spectral energy distributions (SEDs) of this variable AGN in different emission states, and due to its nearness and the improving spatial resolution of new generation telescopes in all wavelength regimes, an attempt could be made to derive SEDs of different parts of the spatially resolved inner region of this AGN. The difficulties and problems to do this are described in this review.