In the American musical theater, the most typical form of structuring musicals has been the book musical, in which songs interrupt spoken dialogue and add means to depict characters and dramatic situations. After 1980, a form of structuring musicals that expands upon the aesthetic conventions of the book musical came to prominence. Sung-through musicals challenged the balance between talking and singing in musical theater in scripts that are entirely or nearly entirely sung. Although often associated with British musicals, this Element focuses on American sung-through musicals composed and premiered between 1980 and 2019. Their creative teams have employed specific procedures and compositional techniques through which music establishes characterization and expression when either very little or nothing is spoken and thus define how the musical reinvented itself toward and in the twenty-first century.