  From hot, tenuous gas dominated by Compton processes, to warm, photoionized
emission-line regions, to cold, optically thick fluorescing matter, accreting
gas flows in X-ray binaries span a huge portion of the parameter space
accessible to astrophysical plasmas. The coexistence of such diverse states of
material within small volumes (10^33-10^36 cm^3) leaves X-ray spectroscopists
with a challenging set of problems, since all such matter produces various
X-ray spectral signatures when exposed to hard X rays. Emission-line regions in
X-ray binaries are characterized by high radiation energy densities, relatively
high particle densities, and velocities ~1000 km/s. In this article, we
describe some recent efforts to generate detailed X-ray line spectra from
models of X-ray binaries, whose aims are to reproduce spectra acquired with the
ASCA, Chandra, and XMM-Newton observatories. With emphasis on the global nature
of X-ray line emission in these systems, the article includes separate
treatments of high-mass and low-mass systems, as well as summaries of continuum
spectroscopy
