The status of GEO 600

The GEO 600 gravitational wave detector located near Hannover in Germany is part of an international network of gravitational wave observatories. As more and more of these detectors approach their final configuration, the focus is shifted from commissioning to detector characterization. At the moment, GEO 600, the first detector using advanced technologies such as dual recycling, is preparing for a long data-taking period starting at the beginning of summer 2006. In this paper, we give an overview of detector commissioning and the detector characterization work of GEO 600 for the period between March 2005 and February 2006.