George Orwell, in Why I Write, details four great motives for writing:
1. Sheer egoism. Desire to seem clever, to be talked about, to be remembered after death, to get your own back on the grown-ups who snubbed you in childhood, etc., etc.
2. Aesthetic enthusiasm. Perception of beauty in the external world, or, on the other hand, in words and their right arrangement.
3. Historical impulse. Desire to see things as they are, to find out true facts and store them up for the use of posterity.
4. Political purpose — using the word “political” in the widest possible sense. Desire to push the world in a certain direction, to alter other peoples’ idea of the kind of society that they should strive after.