A key collaborator and performer, Moissi was among the great European actors who quickly brought Pirandello closer to German-speaking audiences.

"The only possible drama is that, necessarily stripped of all interior drama, of the acceptance of life as it is , after the warning, as a warning to all, of its mysterious terribleness, which for a moment has shaken the characters' existence to its foundations."

His international fame and his "tragic-lyrical" style helped spread Pirandello's works outside Italy, especially in the 1920s. Moissi frequently played characters from Pirandello's works. In the Austro-Germanic world, he is remembered for his stagings of "metatheatrical" dramas (from the "theatre within the theatre" cycle) and for his frequent use of Pirandello's works during his tours. His intense, musical acting (his diction is renowned) was considered particularly suited to the psychological tension and the dimension of "masks" and split identities typical of Pirandello. Contemporary critics recall Pirandello's attention to Moissi as a performer capable of restoring the "tragic edge" beneath the comic or paradoxical surface; various biographical summaries of Moissi mention his "meeting" with Pirandello as an important stage in his career. Contemporary reception (reviews and theatre reports) also underlined the value of his Pirandello-like interpretations. The relationship between the two dates back to the years 1910–1930, a period in which Pirandello was establishing his dramas in Europe ( Six Characters in Search of an Author , 1921; Each in His Own Way , 1924; This Evening We Improvise , 1930) while Moissi, already a star of German theatre, staged modern authors (including Pirandello) to great critical and public acclaim.
The two letters in question concern the staging of Pirandello's drama Non si sa come . The work was composed by Pirandello almost in one go between late July and September 1934, during a holiday in Castiglioncello. In a famous interview given a few months after releasing the work, Pirandello suggested a preferred reading of the text: "Crime belongs to nature, but the truly dramatic moment is that of justice, and it is all the more dramatic the more invisible the court is, that is, in the conscience." Inspired by the short stories Nel gorgo (1913), Cinci (1932) and La realtà del sogno (1914), and conceived to be interpreted by the Austrian actor of Italian-Albanian origins Alexander Moissi , who however died on 23 March 1935, before the staging, the world premiere was in Prague in December 1934, while in Italy it debuted with the Ruggero Ruggeri Company on 13 December 1935 at the Teatro Argentina in Rome.
In the first of the two letters, Pirandello clarifies—with a long and refined argument—the meaning and value of the work. Responding to Moissi's objections, Pirandello delves into the heart of the play and sheds light on his theatrical creation and the poetics of those years. At center stage is the enigma of guilt : how can an "innocent" man commit a horrendous act without truly intending it, and how this invisible fracture destroys lives and relationships. A tragedy of problematic responsibility. Pirandello dismantles the idea that "loving and being honest" is enough to guarantee good: the ego is unstable, conscience is intermittent, guilt can arise where reason cannot reach.