Morphological characteristics of the spike and other rapid human electroencephalographic transients have been examined from graphic and mathematical frames of reference. Wave duration, amplitude, and peak angle, and segmental functions such as rise and descent times and velocities are interrelated wave parameters. Nonetheless, sets of transients, selected on the basis of various attributes of the discharge, may contain quite different groups of deflections. Of the functions examined, segmental velocity, the rate of shift from one voltage level to another, may be most generally useful and informative, providing a way to identify a broad range of wave forms of possible epileptogenic significance that may be without classical spike or spike-wave morphology. Estimations of segmental velocities attained within sinusoidal functions simulating normal electrographic patterns fell largely below 1.5 [mu]v./msec. Those of simulated and naturally occurring spikes and related quasirectilinear wave forms generally exceeded 2 [mu]v./msec.