Guillaume Belanger works as an operation scientist on the Gamma-ray mission Integral in the Science Operations Department of the European Space Agency at ESAC, the European Space Astronomy Centre near Madrid in Spain. His research has been, and still is, firmly anchored to the deepest gravitational well in the Galaxy: Sagittarius A* (Sgr A*). This four-million solar mass black hole whose location defines the nucleus of the Milky Way, is surrounded by a large array of unusal and intimately interacting astrophysical systems. He is interested in the investigation of the ways in which these systems evolve and interact with one another.