Some twenty-three years after the discovery of pulsars and their identification as rotating neutron stars, neutron star physics may be regarded as comingofage. Pul­ sars and accreting neutron stars have now been studied at every wavelength, from the initial radio observations, through optical, X-, and "{-ray, up to the very recent observations in the TeV region, while theorists have studied in some detail relevant physical processes both outside and inside neutron stars. As a result, comparisonof theory with observation provides a test ofour theoretical ideas in fields as diverse as neutron and nuclear matter, superfluidity and superconductivity, the acceleration of high energy particles, and the generation