A novel class of NMR expts., based on the systematic variation of 3 time variables, permits both the identification of exchange networks and the direct measurement of the corresponding rate consts. in soln. Linear combinations of cross sections taken from 2 dimensional spectra allow a straightforward anal. of nonexponential recovery behavior by identifying normal modes. The line widths of the resulting Lorentzian line shapes provide a direct measure of the rate consts. of various dynamic processes, such as chem. exchange, transient Overhauser effects, and spin-lattice relaxation. [on SciFinder (R)]