The Max-Planck-Institut für Plasmaphysik (IPP) is concerned with investigating the physical fundamentals underlying a fusion power plant which - like the sun - is designed to gain energy from the fusion of light atomic nuclei. The two concepts for the magnetic confinement of fusion plasma - →Tokamak arrangement and →stellarator principle - are examined for their power plant suitability at the IPP. In Garching, the ASDEXUpgrade Tokamak and the WENDELSTEIN 7-AS stellarator are operated. The successor WENDELSTEIN 7- X is under preparation at the branch institute of IPP in Greifswald. The work of the IPP is integrated in national and European programmes as well as in world-wide co-operation. On the European level, the IPP presently involved in the largest fusion experiment in the world →JET (Joint European Torus). At the same time, IPP co-operates in the world-wide project for the International Thermonuclear Experimental Reactor →ITER