As developed by Russian Symbolist Nikolai Evreinov (1879-1953) and encapsulated in his book The Theatre in Life (1927), a drama acted or designed to be acted by a single person. The term may also refer to a dramatic representation of what passes in an individual mind, as well as to a musical drama for a solo performer. Everything one witnesses on stage is portrayed from the mental state of the given protagonist.
In opera, a monodrama was originally a melodrama with one role such as Georg Benda's Pygmalion (1779). It is also applied to modern works with a single soloist, such as Schönberg's Die Glückliche Hand (1924), which besides the protagonist has two additional silent roles as well as a choral prologue and epilogue. Erwartung (1924) and La voix humaine (1959) closely follow the traditional definition, while in Eight Songs for a Mad King (1969) and Luzifers Traum (from 1981) the instrumentalists are brought out of the pit to participate in the action.