Joos, Erich2007-07-252007-07-252007-07-251863-7388http://hdl.handle.net/2003/2448310.17877/DE290R-7012In this paper I review the fundamentals of decoherence theory. Decoherence is viewed as a straightforward application of the general kinematical concept of a quantum wave function. Classical notions (such as ``particle") as well as secondary quantum concepts (such as ``observable'', superselection rule etc.) can be derived. Special emphasis is put on a precise and consistent interpretation of quantum states and processes.enPhysics & Philosophy ; 10classical physicsdecoherenceinterpretations of quantum mechanicsirreversibilityquantum-classical relationquantum measurement100530article (journal)