  In this talk I present recent developments in chiral dynamics of hadrons and
hadrons in a medium addressing the following points: interaction of the octet
of pseudoscalar mesons with the octet of baryons of the nucleon, showing recent
experimental evidence on the existence of two $\Lambda(1405)$ states, the
interaction of the octet of pseudoscalar mesons with the decuplet of baryons of
the $\Delta$, with particular emphasis on the $\Lambda(1520)$ resonance,
dynamically generated by this interaction. Then I review the interaction of
kaons in a nuclear medium and briefly discuss the situation around the claims
of deeply bound states in nuclei. The large renormalization of the
$\Lambda(1520)$ in the nuclear medium is shown as another example of successful
application of the chiral unitary techniques.
