For decades, a number of attempts have been made to define the processes of vowel perception. Understanding this cognitive process at the most fundamental level has the potential of improving communication applications and speech processing diagnostics. The Waveform Model of Vowel Perception and Production approaches the problem from the unique perspective found in waveform displays. The visual patterns led to a unique method of vowel categorization and identification. In addition to explaining perception, organizing the articulatory positions of the lips and tongue by the Waveform Model categorization showed that each feature in the waveform signal can be associated with a specific articulatory gesture. The categorical relationships also led to an explanation of perceptual errors. A successful model of vowels should account for perception, production, and errors, but the Waveform Model is the first to explain and incorporate each of these aspects into one comprehensive model. In support of the Waveform Model, 97.7% accuracy across the vowels produced by 20 male talkers is described in the Waveform Model book. To replicate and improve upon these results, the 50 male talkers in the robust Hillenbrand et al. dataset (1995) were processed using the Waveform Model methods with 99.2% accuracy being achieved (first public discussion of these results; the 161st meeting of the Acoustical Society of America in May, 2011). In summary, the Waveform Model explains vowel perception, production, and errors, and the evidence demonstrating its effectiveness is growing. The Waveform Model is explaining vowel processing at the most fundamental level.