[en] The first part of this thesis considers K^- → π^- reactions on deuterium. The interactions between the final state hyperon and nucleon produced are modelled using one-boson-exchange-potentials in a coupled channel treatment. It is found that the potentials considered describe the available data well, including the large enhancement observed, in the spectrum of the lambda-proton final states, at the Σ⁺n threshold. The second part deals with K^- → π^-reactions at 0⁰ on complex nuclei. A simple shell model of the nucleus is used in a calculation of the rates for the formation of lambda-hypernuclei, the objective being to analyse the relative contributions to the observed spectra, from the coherent excitation of the so-called strangeness-analogue-state, and from incoherent transitions. In the full calculation, the kaon and pion wavefunctions are treated in the framework of the distorted-wave-impulse-approximation, and the shapes of the calculated spectra are found to be in general agreement with experiment. (author)