* Plays: He wrote several plays, including "The Show Must Go On" (1971), "The Return of the King" (1975), and "The Hour of the Wolf" (1979). He also collaborated with Ingmar Bergman on the play "The Serpent's Egg" (1977), though it's attributed to Bergman.
* Screenplays: He contributed to the screenplays of several Ingmar Bergman films, including "The Silence" (1963), "Persona" (1966), "Hour of the Wolf" (1968), and "Shame" (1968).
* Autobiography: He wrote an autobiography titled "En Skådespelares Minnen" (An Actor's Memories), which was published in 2002.
While his writing career is less prominent than his acting, he was a significant figure in Swedish theatre and cinema.