In the 1970s, 80s, and 90s, a great deal of theoretical work commenced on the problem of giving a fully quantum-theoretic account of measurement. This work comprises the programs of decoherence of W. Zurek 1982 and H. D. Zeh 1973 and the consistent histories approach of Griffiths 1984, Omnès1988, and Gell-Mann and Hartle 1990, 1993.
