After encountering il sgit de many times (and each time avoiding the pain to find its exact meaning) I decided to do what I haven’t done for some time now – use the dictionary.
As per the Oxford Starter French Dictionary, s’agir de = to be about. This is as confusing as the meaning given in the book, Complete French: s’agir de = to be a matter of. Fortunately, good dictionaries throw in example sentences. And this Oxford dictionary is a good one, though very basic.
De quoi s’agit il? = what’s it about?
Ah! I got it. But then I could make this much simpler: De quoi est il?
Laissez-moi penser à un autre exemple. Let me think of another example.
It is about a woman. (Don't ask me why this sentence came to my mind!). Using s'agir de the translation goes as follows: Il s'agit d'une femme. This definitely sounds better than Il est sujet d'une femme.
I hope I have understood the usage.
Hmmm… time to buy a better French dictionary. One that has lots of example sentences.