The Munsell color order system was rigorously defined for illuminant, observer, and surround. Using Nayatani's nonlinear model of chromatic adaptation, approximately color-constant 1931 CIE tristimulus values for the notations of the Munsell Book of Color were calculated for a variety of continuous-spectrum illuminants. Several linear-programming models were developed for generating spectral reflectance functions that integrate to these tristimulus values. Experimental methods and results are discussed. -- AATA