The High Energy Focusing Telescope (HEFT) is a balloon-borne experiment employing focusing optics in the hard X-ray/soft gamma-ray band (20 - 100 keV) for sensitive observations of astrophysical sources. The primary scientific objectives include imaging and spectroscopy of 44Ti emission in young supernova remnants, sensitive hard X-ray observations of obscured Active Galactic Nuclei, and spectroscopic observations of accreting high-magnetic field pulsars. Over the last four years, we have developed grazing-incidence depth-graded multilayer optics and high spectral resolution solid stat Cadmium Zinc Telluride pixel detectors in order to assemble a balloon-borne experiment with sensitivity and imaging capability superior to previous satellite missions operating in this band. In this paper, we describe the instrument design, and present recent laboratory demonstrations of the optics and detector technologies.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.