  The historical detection of gravitational waves emitted from the binary
neutron star merger GW170817 has opened the new era of multi-messenger
astronomy. Since then, many other significant discoveries -- both on heaven and
earth -- are providing new clues into the behavior of neutron-rich matter. It
is the goal of this article to illustrate how the remarkable progress made
during the last few years is spearheading the field into the golden age of
neutron-star physics.
