Ayn Rand has this tendency to lecture about things in her writing. This drives some people crazy but for me, I love that she has fossilized some very clear thinking about what is and what is not.

For instance… Where is the line between a novel and a short story? Before I read this, I would have said something meandering, vague, and fuzzy:

The first requirement of a short story is that it must be built around one single incident. It can be an incident which is complete in itself, or it can be an incident which summarizes and climaxes a long development of events, but it must be a single incident, like a sharp focus. Otherwise it is not the construction of a short story, but of a novel, mo matter what the length. Length is not the standard by which one differentiates a short story from a novel; the method of construction is. One cannot take a broad view of a subject, such as one takes for a novel, and say: “I will make it a short story by telling it briefly.” One must take a subject which can be brought into one focus, one concrete incident, and build the narrative around it.

(From Letter to Gerald Loeb, vice president of E.F. Hutton and Co. dated Jan 15, 1943)

…but Rand has such stark views on things that you know exactly where she would drop a line and, if you’re not too busy taking the lecture personally, you can benefit from her clarity.

She goes on to discuss, in the context the particular story she has just read by Mr. Loeb, which incident would have been the crucial one to present and why. I’ll cherry pick sentences so that we get a more concise reading:

…you must show one scene between your characters in detail, with action and dialogue. that scene must be a crucial one, not just an incidental one chosen at random, but a scene that climaxes the rest and resolves the theme of the story..
What is the theme of your story?…
The scene in which he finds it out, the scene where the woman shows her real character and the man receives a dreadful, tragic disappointment… that scene must be written and presented in detail. Then you’ll have a proper short story form.
…the reader has been reading a long general narrative, getting acquainted with the characters and waiting for the climax when he would see them in action. That unwritten scene is the local climax. If the reader does not see it–nor any other specific scene–he feels cheated. And you cannot choose another scene for a focus, because in a short story it is the crucial scene that must be featured.

So… short stories should focus on the one crucial scene, we should see the characters in action and dialogue, and there should be a climax so the reader isn’t left feeling blue.

Got it! :) Now to get to the writing.

PS - You can buy Rand’s book of letters on Amazon.com.  I have really enjoyed reading a few letters each morning.  It is a very relaxing yet invigorating way to start my days.