  The Cherenkov Telescope Array Observatory (CTAO) is a next-generation
facility for ground-based very high energy gamma ray astronomy. CTAO will be
operated as an open observatory. With two sites, in the northern and southern
hemispheres, the Cherenkov Telescope Array CTA will provide full-sky coverage,
improving sensitivity by an order of magnitude over current instruments, with a
wide gamma ray energy coverage from 20 GeV to 300 TeV. CTA will use telescope
arrays composed of three types of telescopes, optimized to cover different
energy ranges. The large telescopes covering the lowest energies provide rapid
slewing capability, for follow-up of transients. Key Science Projects (KSPs)
are developed to form a significant part of the CTAO observing program during
the first decade of operation, providing legacy data sets such as surveys or
deep observations of key targets.
