<title>DEIMOS: a wide-field faint-object spectrograph</title>

This paper describes the design of DEIMOS -- a dual beam, off axis, multi object spectrograph of medium resolution, being designed for the Keck II telescope on Mauna Kea in Hawaii. The difficult and advanced scientific goals of the DEIMOS project have generated many challenging design requirements. The DEIMOS team at Lick Observatory has been responding to these challenges with new and unique concepts in instrument design and fabrication.