  We review the formation and evolution of compact binary stars consisting of
white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of
compact binary stars are expected to be the most important sources for the
forthcoming gravitational-wave (GW) astronomy. In the first part of the review,
we discuss observational manifestations of close binary stars with NS and/or
black components and their merger rate, crucial points in the formation and
evolution of compact stars in binary systems, including the treatment of the
natal kicks which NSs and BHs acquire during the core collapse of massive stars
and the common envelope phase of binary evolution, which are most relevant to
the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the
review is devoted mainly to formation and evolution of binary WDs and their
observational manifestations, including their role as progenitors of
cosmologically important thermonuclear SN Ia. We also consider AM CVn-stars
which are thought to be the best verification binary GW sources for future
low-frequency GW space interferometers.
