6th NATO-Advanced-Study-Institute on Electromagnetic Spectrum of Neutron Stars, Marmaris, Turkey, 7 - 18 June 2004, vol.210, pp.263-277, (Full Text)
I will review the class of accreting powered neutron stars that are in close binary systems. I will summarize the recent developments and the main properties of the neutron stars. These include the formation of X-ray spectra, formation of pulse profiles, quasi periodic oscillations, pulse frequency fluctuations, long term variations and orbital period decay of X-ray binaries.