  Merger events of close double neutron stars (DNS) lie at the basis of a
number of current issues in relativistic astrophysics, such as the indirect and
possible direct detection of gravitational waves, the production of gamma-ray
bursts at cosmological distances, and the origin of r-process elements in the
universe. In assessing the importance or relevance of DNS coalescence to these
issues, knowledge of the rate of coalescence in our Galaxy is required. In this
paper, I review the current estimates of the DNS merger rate (theoretical and
empirical) and discuss new ways to obtain limits on this rate using all
information available at present.
