My research interest as an observational astrophysicist is the evolution of active galactic nuclei (AGN) and their host galaxies. I mainly focus on quasars, the most luminous active galaxies known, which can tell us something about the growth phase of the black hole. I want to get a better understanding of the tight correlations found between the black hole and the properties of their host galaxies. Therefore I use high angular resolution multi-band imaging to study the properties of the host galaxies out to high redshifts. Lately I am also involved in observational campaigns using spatially resolved integral field spectroscopy with the aim to explain the unusual stellar population properties of AGN host galaxies and to collect evidence for AGN driven outflows and their relevance for the evolution of these galaxies.