X-ray imaging of the aurora

X-ray imaging has proved to be a powerful technique for remote mapping of the precipitation of energetic electrons, providing spatial, temporal and spectral information on the precipitating electrons both at day and night. The strengths and weaknesses of the X-ray imaging technique compared to auroral imaging in the visible and ultra-violet spectral ranges are discussed. A short review is given of the development in this field, including some future plans. Some of the results obtained from auroral X-ray studies are discussed.