The allusions to drama and theatre are made explicit in this novel through the title and the way that Dunstan, the narrator of this story, comes to view himself as being "Fifth Business," that fifth character who has no opposite pairing, but whose function is to make the plot work through how he connects the other characters. Dunstan himself draws upon his identity as Fifth Business at various points in the text to explain his actions, such as his disclosure to both Paul Dempster and Boyd Staunton about Paul's unfortunate premature birth. Stemming from this rich thematic vein of drama and theatre in the text, it is clear that the central message of this text concerns identifying one's role in life and then determining to play it. Liesl rebukes Dunstan for living a life that, in her words, is "not lived" because it is bogged down by guilt and a Presbyterian sense of right and wrong. She makes the following suggestion to him:

Why don't you shake hands with your devil, Ramsay, and change this foolish life of yours? Why don't you, just for once, do something inexplicable, irrational, at the devil's bidding, and just for the hell of it? You would be a very different man.

The narrator has played various roles throughout the entire novel up until this point: guilt-stricken villain, war hero, friend, erratic school master. Liesl encourages him to live for himself and express who he really is rather than not living and living other roles that are not really an expression of his identity. The message of this novel is therefore to find your role and then to live it, rather than to live the other roles that others--friends, parents, society--would have you live. It is after this conversation that Dunstan experiences "deep healing tenderness," which indicates how important this message is to him.

How is the theme of drama and theatre developed in Fifth Business?

As the novel's title strongly suggests, the traditions of stage drama and theatre, most particularly found in opera, are a key thematic concern of this text, most particularly in the way that characterisation is explored. This is made explicit at the very end of the fifth section of the novel, where Liesl explains to the narrator her theory on Dunstan's character and what role he plays, and how in particular he relates to the "Fifth Business," who relates to the other stock characters and produces the necessary element of drama through his interactions:

The prima donna and the tenor, the contralto and the basso, get all the best music and do all the spectacular things, but you cannot manage the plot without Fifth Business! It is not spectacular, but it is a good line of work, I can tell you, and those who play it sometimes have a career that outlasts the golden voices.

The theme of drama and theatre therefore relates to the title of the novel, and also the state of being "Fifth Business," which quite clearly is Dunstan's role in this novel and in the strange network of relationships he finds himself working within. In particular, Dunstan comes to explain his actions as to why he disclosed to Paul Dempster the secret behind his birth, and Boy Staunton's involvement in it, as being part of his role as "Fifth Business." He, as Liesl identifies, knows the secret of the hero's birth, and is, indirectly at least, the cause of Boy Staunton's death because of this revelation. Drama and theatre therefore lie at the very heart of this novel as the author uses this theme to develop role and character.