A review of soft X-ray astronomy

Developments and problems in soft (200 eV to 2 keV) X-ray astronomy are reviewed. The distribution of X-ray sources in the galaxy as determined from UHURU data is described, and the properties of three strong sources of soft X-rays (Cygnus Loop, Vela X, Puppis A) are summarized. The problem of X-ray absorption in the interstellar medium is discussed, the absolute luminosity of several discrete sources is determined, and results are considered for soft X-ray absorption measurements of the Crab pulsars. The existence of a diffuse soft X-ray background is noted.