  An effective chiral Lagrangian in heavy-fermion formalism whose parameters
are constrained by kaon-nucleon and kaon-nuclear interactions next to the
leading order in chiral expansion is used to describe kaon condensation in
dense ``neutron star" matter. The critical density is found to be robust with
respect to the parameters of the chiral Lagrangian and comes out to be
$\rho_c\sim (3 - 4)\rho_0$. Once kaon condensation sets in, the system is no
longer composed of neutron matter but of nuclear matter. Possible consequences
on stellar collapse with the formation of compact ``nuclear stars" or
light-mass black holes are pointed out.
