A hydrostatic high pressure apparatus capable of achieving 18 kilobars at room temperature, 14.1 kilobars at 77°K, and limited in pressure at lower temperatures only by the freezing of helium is described. A number of techniques facilitating construction, operation, and repair are described. An experimental pressure vessel and cryostat for optical studies to 16 kilobars in the temperature range from 370° to approximately 60°K are also discussed.