Theories of accreting x-ray pulsars

We review current models of X-ray pulsars in the light of our observational knowledge. The physics of the accretion column and the polar cap are discussed, and the main physical processes described, emphasizing the peculiarities introduced by the strong magnetic field. Radiative transfer methods adapted to these extreme conditions are outlined. We then discuss recent calculations on the self-consistent structure of the X-ray emission region, aimed at providing realistic theoretical spectra and pulse shapes