In English, usually general terms come without the definite article (THE) - as far as i know as I'm not a native English speaker. I like talking about THE writing makes the sentence seem to be about a specific writing (some specific paper or the style of writing of some article ...etc). However, speaking about the art of writing in general, do not require the definite article THE.
Here we get specific a bit I'd say.
Like, what is this writing? novel? short story? graffiti even? article in newspaper? So, the term according to that is used.
On the other hand, there is a term that is usually used in plural and that is: كتابات (kitábát) which is probably the meaning you are seeking and it could be imagined as the plural of كتابة, but the thing with this word is that I don't see it used separately; It is mostly used with something else (a name commonly). For example: I love the writings of Gibran أحب كتابات جبران.
In your example, this might be true though I didn't quite see this expression myself in literature, but little adjustment: hádhihi هذه (since al-kitábah is feminine).
In Arabic things work by roots. Roots are usually 3 consonants linked together for a general idea, and derivations according to specific models is done over the root to derive more words. Al-Kitaabah and Kitaab are both from the root (K T B) which deals with writing in one way or another. Other words related:
- Maktabah: مكتبة (library/bookshop/stationary shop).
- Maktoob: مكتوب (sometimes used for "letter").
- Maktab: مكتب (office).
And probably there are a number of them but memory doesn't serve me much right now. Since "book" is a written thing, so it does sound logical to link it to the root (KTB) which deals with everything has to do with writing.