In the short story, "The Open Window," by Saki, the author writes to entertain. That is the point of the author's story. He uses Vera, a mischievous niece, to tell a tall tale, that frightens Framton Nuttel. Overall, the story is entertaining from the beginning of Vera's tall tale until the end of the tall tale. Not only is Mr. Nuttel afraid when the three men begin walking toward the open window, but the reader is just as uneasy.
The short story offers not only entertainment, but it offers insight into the heart of mankind. The theme is deception. Without the niece's deception, there would be no story:
Were it not for deception, this story could not happen. The action and irony of the story revolve around the apparent deception that Mrs. Sappleton's niece practices. It remains to be seen, however, whether this deception is a harmless prank or the result of a sinister disposition. If the niece's deception is cruel, then the reader must question the motives behind the deception practiced by all tellers of stories, including Saki himself.
Also, the theme of appearance versus reality is evident in this story. Can it be for real that these men are walking toward the open window after four years of being missing. What is real and what is not real:
When Mr. Nuttel (and the reader) are presented with a contrary reality at the end of the story, the result is a tension between appearance and reality that needs to be resolved: Which is real? Can they both be real?
Finally, there is a theme of sanity versus sanity. There is a fine line line between the two. Is Mr. Nuttel losing his mind right along with Mrs. Sappleton? Apparently, he can see what she can see and should not be seeing:
Nuttel's susceptibility to deceit is no different from that of the reader of the story. Yet Mr. Nuttel is insane, and the reader, presumably, is not. In order to maintain this distinction, Saki forces his reader to consider the nature of insanity and its causes.
The above themes entertain the reader and keep the reader in suspense until the end of the Vera's tall tale.