The Fermi Gamma-ray Space Telescope is opening a wide new window on the universe. Gamma rays are the highest-energy form of light, and the gamma-ray sky is radically different from the one we perceive with our own eyes. Fermi is advancing our understanding of a broad range of topics, including supermassive black holes, dark matter studies, the physics of pulsars and gamma-rays bursts, and the origin of cosmic rays. The mission observes high-energy gamma rays over a broad range of energies as well as more focused gamma-ray bursts. Fermi was launched in 2008.