Active galactic nuclei (AGN) are one of the most luminous objects in the
Universe, emitting powerful continuum and line emission across all wavelength
bands. They represent an important link in the investigations of the galaxy
evolution and cosmology. The resolving of the AGN inner structure is still a
difficult task with current instruments, therefore the spectroscopy and
spectropolarimetry are crucial tools to investigate these objects and their
components, such as the properties of the supermassive black hole, the broad
line region, and the dusty torus. In this review, we present the results of the
project "Astrophysical spectroscopy of extragalactic objects", from the
observations, data processing and analysis, to the modelling of different
regions in AGN.Comment: Proceedings of the Serbian Astronomical Conference 201