Information transfer in quantum measurements: irreversibility and amplification

The aim of these lectures is to investigate the transfer of information occurring in course of quantum interactions. In particular, I shall explore circumstances in which such an information transfer with the quantum environment of the considered quantum system leads to the destruction of the phase coherence between the states of the privileged basis in the system Hilbert space. This basis shall be called the pointer basis. I shall argue that states of this pointer basis correspond to the ``classical'' states of the observables of the quantum system in question.