The University of California is planning to build a segmented, ten-meter effective diameter optical and infrared telescope for use by its astronomers. The anticipated site for the telescope is Mauna Kea, Hawaii. The details of the design and the current activities on prototypes as well as a technical demonstration will be described. The design employs 36 actively controlled hexagonal mirror segments that form a mosaic primary mirror. As the primary will be parabolic, the segments will be off-axis sections of a paraboloid, each segment to be 7.5 cm thick and 1.8 m in diameter. The segments will be polished to their desired shape by stressed mirror polishing, a technique for making non-axisymmetric surfaces. The active control system employs displacement sensors at the edges of the segments that allow the positions of all the mirror segments to be determined; the segments' positions are adjusted by three displacement actuators per segment. The basic characteristics of the control system and its critical components will be described. The overall optical design of the telescope will be a Pitchey-Cretien f/1.75 - f/15 system. The goals and the design of the surrounding building and dome will be described. The dome is extremely compact, and rotates on a stationary building in the manner of conventional telescope domes.