Stuart is best known for his discoveries on the nature of Maya hieroglyphic writing from the 1980s to the present. By 1985 scholars had already generally recognized that there were two types of signs in the script: logograms (word signs) and syllables (consonant-vowel or CV). However, only a limited amount of Maya texts could be read in their original language, Classic Mayan, due to an imprecise understanding of the visual nature of the script, especially the ways signs formed and combined. Stuart demonstrated that signs could have a great many variants and forms, all visually distinct yet functionally equivalent. The recognition of the principles behind graphic variation and structure helped lead to a number of breakthroughs. Stuart proposed the decipherments of many new syllables and logograms in the 1980s and 1990s, which in turn provided a more firm basis for a new wave of linguistic analyses of Maya texts during the 1990s and early 2000s.