The National Aeronautics and Space Administration is developing a 2.4 meter aperture astronomical telescope, the Space Telescope, to be placed in earth orbit in the early 1980s. Free of the earth's atmosphere, this international observatory will provide astronomers with an electromagnetic window from the far ultraviolet to the near infrared. Moreover, the Space Telescope is being designed to provide near-diffraction limited imagery at visible and longer wavelengths which will provide angular resolution that surpasses the largest of ground based observatories. This paper reviews the optical technology that has been developed over the last decade to bring the Space Telescope to a practical reality. The optical design of the telescope, the optical performance control system, and the anticipated orbital performance is presented as well. In addition, the initial complement of focal plane instruments, being developed concurrently, is described.