A critical job of the auditory system is to localize sounds, which depends upon spectral cues provided by the filtering of the pinna for vertical localization and interaural time (ITDs) and level disparities (ILDs) for horizontal localization. We found anatomical and physiological specializations in the circuits that encode these cues. Cells in the medial superior olive (MSO) function as high resolution coincidence detectors or cross-correlators and their inputs have enhanced temporal synchronization compared to auditory nerve fibers, and the speed of the calyx of Held synapse helps to convey the inhibitory input from the contralateral ear to the LSO synchronously with the excitatory input from the ipsilateral ear even though it has to travel farther with an additional synapse. We have also been studying the psychoacoustics of sound localization in the cat by training them to look at sounds. Cats demonstrate high accuracy and precision when localizing with their head unrestrained. Their mobile ears have a reflex in response to head movement that keeps the ears pointed toward the sound source despite head movements. Cats also experience the precedence effect and a physiological correlate of the effect can be seen in recordings from the inferior colliculus.