In this chapter the standard treatments of the Transeurasian vowel correspondences are reviewed, including their reconstructions of hypothetical proto-inventories, for the purpose of establishing a description of the Transeurasian vowel inventory and vowel harmony type. The review commences with a comparison of two major types of vowel-harmony systems in the Transeurasian languages, i.e. the palatal vs. the tongue-root harmony systems, and presents phonetic, phonological, and comparative evidence for a tongue-root harmony analysis of Korean, Mongolic, and Tungusic. Interpretations of the main Transeurasian reconstructions are then proposed, such as Ramstedt (1952–66) and Poppe (1960b) according to tongue-root harmony analysis as opposed to the conventional palatal harmony analysis. After this, there is an effort to situate the Transeurasian vowel inventory in its typological and geographical neighborhood, including Northeast Asian languages and beyond, and in its linguistic geographical setting.