  In these lectures we discuss the investigation of the strange meson
production in proton-proton ($pp$) and in proton-nucleus ($pA$) reactions
within an effective Lagrangian model. The kaon production proceeds mainly via
the excitations of $N^*$(1650), $N^*$(1710), and $N^*$(1720) resonant
intermediate nucleonic states, in the collision of two initial state nucleons.
Therefore, the strangeness production is expected to provide information about
the resonances lying at higher excitation energies. For beam energies very
close to the kaon production threshold the hyperon-proton final state
interaction effects are quite important. Thus, these studies provide a check on
the models of hyperon-nucleon interactions. The in-medium production of kaons
show strong sensitivity to the self energies of the intermediate mesons.
