Themes play an important role. In a short fictional book like 'The Metamorphosis', the theme of alienation is powerfully presented through the transformation of the main character into an insect. This makes the reader think about human nature and society, even though it's a short read.
Generally, a short fictional book might have around 30,000 to 40,000 words. This gives enough space to develop a plot and characters without being overly lengthy. However, some could be shorter, like 15,000 words, if the story is very focused and concise.
'Shantaram' is a fictional book. It has fictional characters and a fictional storyline. It may have some elements that seem real - life - inspired, but overall it's a work of fiction.
It's fiction. The story in 'The Shack' is made up by the author. It contains elements like a special place (the shack) and interactions that are more in the realm of imagination. It might touch on real - life themes like faith and relationships, but the overall story is fictional.