The author analyses the substantial contribution made by American composers to the development of twentieth-century opera. The methodological approach employed in this book is influenced by Mieczyslaw Tomaszewski's method of integral interpretation. The operas analyzed in this monograph, written from 1976 onwards, represent a watershed in twentieth-century American opera, characterised by three main aspects: firstly, creation of video-opera, represented by the works of Steve Reich, secondly, creation of a new kind of opera based on topics related to contemporary events that are manifested with documentary fidelity, represented by works of John Adams, and lastly, the introduction of a new genre: a portrait opera, characteristic for the works of Philip Glass.