The Fortune of the Rougons by Emile Zola
Why does anyone get this into their head to do this? At some point Emile Zola decided that it would be a good idea to write a huge series of novels based around the interlinked tales of one family.
The whole series would take him over twenty years and finish up comprising twenty separate full sized novels. One of them, Germinal, would go on to become one of the great classic novels. It would be easy to regard the whole series as one of the all time classics of mission creep. But in the introduction to the very first one of them, the Fortune of the Rougons, Zola makes it clear that the large scale of the project was something that he conceived from the very beginning.
