  The Visible and Infrared Survey Telescope for Astronomy (VISTA) is the
4-metre wide-field survey telescope at ESO's Paranal Observatory, equipped with
the world's largest near-infrared imaging camera (VISTA IR Camera, VIRCAM),
with 1.65 degree diameter field of view, and 67 Mpixels giving 0.6 square
degrees active pixel area, operating at wavelengths 0.8 - 2.3 microns. We
provide a short history of the project, and an overview of the technical
details of the full system including the optical design, mirrors, telescope
structure, IR camera, active optics, enclosure and software. The system
includes several innovative design features such as the f/1 primary mirror, the
dichroic cold-baffle camera design and the sophisticated wavefront sensing
system delivering closed-loop 5-axis alignment of the secondary mirror. We
conclude with a summary of the delivered performance, and a short overview of
the six ESO public surveys in progress on VISTA.
