The Fermi Gamma-ray Space Telescope, formerly named GLAST, is a mission in low-Earth orbit to observe gamma rays from the cosmos in the broad energy range from 20 MeV to >300 GeV, with supporting observations of gamma-ray bursts from 8 keV to 30 MeV. The telescope far surpasses previous generations in its ability to detect and localize faint gamma-ray sources, as well as its ability to see 20% of the sky at any instant and scan the entire sky on a timescale of a few hours. With its launch on 11 June 2008, Fermi opened a new and exciting window on a wide variety of exotic astrophysical objects and is enabling new research on such topics as the origin and circulation of cosmic rays and searches for hypothetical new phenomena such as annihilation of dark matter. In addition to introducing the mission and the instruments, we summarize the latest catalogs of sources, including active galaxies and pulsars, and we present some of the latest results on diffuse gamma-ray production, dark matter searches, and gamma-ray bursts.