Recent measurements obtained with a variety of techniques have extended von Békésy's observations of cochlear-partition mechanics including the traveling-wave pattern and the frequency-place relation. Whereas the cochlear fiber has been shown to be sharper than expected, on the basis of Békésy's results, it apparently is not sharp enough to account for the frequency selectivity observed in auditory nerve fibers. The main remaining question is whether the vibration of the basilar membrane is linear or not. Steady-state nonlinearities that disappear rapidly upon death, transient nonlinear response, and two-tone suppression have been observed in the mid-frequency range in one animal species. Whether the linearity-nonlinearity controversy arises from a species difference or a frequency-place difference remains to be resolved.