  An analysis of the rare B decays $B\to K^{(*)}\nu\bar\nu$ is presented both
within the SM and beyond. The SM predictions for the branching ratios are
updated and uncertainties reduced. For the NP analysis both a model independent
approach is used and concrete NP models are studied. The relations between
$b\to s\nu\bar\nu$ and $b\to s\ell^+\ell^-$ transitions are analysed in detail.
