  We examine the presence of strangeness-bearing components, hyperons and
kaons, in dense neutron star matter. Calculations are performed using
relativistic mean field models, in which both the baryon-baryon and kaon-baryon
interactions are mediated by meson exchange. Results of kaon condensation are
found to be qualitatively similar to previous work with chiral models, if
compatibility of the kaon optical potentials is required. The presence of
strangeness, be it in the form of hyperons or kaons, implies a reduction in the
maximum mass and a relatively large number of protons, sufficient to allow
rapid cooling to take place. The need to improve upon the poorly-known
couplings of the strange particles, which determine the composition and
structure of neutron stars, is stressed. We also discuss generic problems with
effective masses in mean field theories.
