Over the last few decades, considerable effort has been expended in adapting a range of group II to VI compound semiconductors for use as photon and charged particle detectors with a particular emphasis on the hard X- and gamma-ray wavebands. Whilst Si and Ge have become detection standards for energy dispersive spectroscopy in the laboratory, their use in commercial and industrial environments is limited - mainly by the need for expensive and bulky cryogenics. Wide-gap compound semiconductors offer the possibility of room temperature operation, while still maintaining sub-keV spectral resolution at hard X-ray wavelengths. At the present time, the performances of such devices are not yet close to the Fano limit (and ultimately, as a result of their higher band-gap, they can never achieve the spectral performances of Si or Ge), however, spectroscopically they can already satisfy the requirements of most of the future anticipated applications above 10 keV. In this paper, we review current progress in compound semiconductors and present results from our development program aimed at producing monolithic compound semiconductor detectors and large area arrays for the next generation X-ray astrophysics and planetary space missions.