What do you think is the principal message of "The Open Window" by H. H. Munro?

I would want to argue that there are probably many
messages that can be extracted from this excellent story. Clearly, the major message
that we can identify is linked to the power of storytelling and how the power of a good
story is celebrated by recognising the impact that it can have over a susceptible
audience. Note the way in which Vera is presented as a master storyteller without
compare. She is able to quickly identify Framton Nuttel's susceptibility and acts with
verve and imagination to tell him a story with spectacular results. Then, having to
explain the swift exit that he takes after the "ghosts" enter through the open window of
the title, she does it again, this time using a story to trick her relatives. As we
re-read the story after our first reading, we are amazed at the skill in which Vera
sounds out her victim, making sure that he knows nothing about her aunt before
unleashing her tale.

Thus we can see that this story is
above all about the way that a gifted storyteller can use stories with devastating
impact to manipulate those around them. It is thus a warning and a celebration of the
power of storytelling, as poor Framton Nuttel gives testament to. I doubt whether his
meeting with Vera helped his nervous condition!