Description: (Applicant's Description) The X-ray Crystallography has had a long history as an important research element of the Cancer Center. It provides state-of-the-art x-ray diffraction instrumentation (four Rigaku rotating anode x-ray generators, three Siemans Multiwire area detectors, one MacScience diffraction image processor, a Rigaku R-axis IIc, and a Rigaku R-axis IV) and computer/graphics (SGI Power Onyx, two SGI Maximum Impact graphic stations, a new Origin 2000 compute server and a DEC Alpha 2200 server). The facility supports the work of seven Cancer Center crystallographers who have multiple collaborations with Cancer Center faculty in other programs. The facility provided computer/graphics support to 51 faculty in 8 programs this past year. The facility is housed in 6,500 NASF of Cancer Center space as well as a 1,200 NASF "virtual" theater for Power Onyx-linked large screen three-dimensional stereo projection. The facility is an integral component of the Cancer Center's Structural Biology Program with an emphasis on structure: function relationships, molecular modeling and drug design.