[en] It has been shown that under certain conditions ''complex plasmas'' (plasma containing ions, electrons and charged microspheres) may undergo spontaneous phase changes to become liquid and crystalline, without recombination of the charge components. Hence these systems may be regarded as new plasma states - ''condensed plasmas''. Complex plasmas are of great interest from a fundamental research point of view because the individual particles of one plasma component (the charged microspheres) can be visualised and hence the plasma can be studied at the kinetic level. In this introduction the potential of complex plasmas will be presented through dedicated experiments performed in the laboratory and under microgravity conditions. (orig.)