The scientific objectives, status, and future instrumental requirements of high energy X-ray astronomy (~20 to 200 keV) are discussed. Two particularly compelling requirements are: (1) an improvement in sensitivity to a level of~5 microCrab (5 x 10↑(-6) of the flux from the Crab Nebula), which is a factor of 100 improvement over the next-generation space instruments now in development and will make several hundred thousand X-ray sources accessible to observation; and (2) a survey of the sky at a sensitivity of -0.1 milliCrab, which will discover and characterize -10,000 new sources. The first requirement can be fulfilled by imaging telescopes that use large-area focusing X-ray mirrors, which are effective over ~5 - 30 arc minute fields, and the second requirement can be met by arrays of large area coded mask imagers with wide fields, -50°. Multilayer mirror and CdZnTe detector technology now in development offer the potential to meet these objectives. Position-sensitive CdZnTe detectors are well-suited to bo h of these imaging techniques and instrument concepts that use these detectors are described. Detectors with pixel readout are better suited for focusing telescopes and those with crossed-strip readout is better suited for coded mask imagers. Technical aspects of these detectors are discussed. Recent work at UCSD and WU on CdZnTe strip detectors is described in detail. Here studies with small, -40 micron, X-ray beams have mapped a crossed-strip detector's spatial response with fine spatial resolution. The results demonstrate that crossed strip detectors have many desirable properties for both spatial and spectral measurements. They also show there are irregularities in the spatial properties which may limit detector performance on small scales.
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