This monograph studies opera as music drama, guided by four ideas: opera as an ambiance (setting an acoustic stage where dramatic action becomes possible), as a Gesamtkunstwerk (incorporating other arts forms into a coherent whole), as archaeology (revivifying lost worlds of experience) and as a dialectical syllogism (resulting in the negation of a paralysing negation via a dramatic act). We focus on Richard Wagner, as composer and author, but also address other music dramas (by Giacomo Puccini and John Adams), adopting a Hegelian dialectical perspective, but involving other dialectical thinkers (e.g., Marx and Engels) as well.