The HEADS-Brera On-Line Service (HEADS = High Energy Astrophysics Database Service) is maintained at the Astronomical Observatory of Brera, Milano, Italy. It is based on the EXOSAT Database System currently developed mainly by NASA's HEASARC (§3.2.6.). HEADS currently provides access to data from a number of past observatories (e.g., Einstein and EXOSAT) and will gradually be extended to include the public data archives of current and upcoming missions. The service also provides access to catalogs, results and data products (images, spectra, light curves) and dedicated analysis packages. There is considerable overlap in the data available through HEASARC, HEADS, EXOSAT, and Leicester (UK), but HEADS supports the complete set of data products (with the exclusion of the ROSAT data, that, in any case, can be obtained from HEADS through the HEASARC database). Login is either via SET HOST ASTMIB (32469) or telnet to astmib.mi.astro.it (192.167.37.2) and login as user xray; no password is required. For a quick reference guide or further inquiries contact either L. Stella (stella@astmim.mi.astro.it) or G. Tagliaferri (tagliaferri@astmim.mi.astro.it). [Reference: Tagliaferri and Stella (1993).]