working on a novel

Who is the most prolific writer? At first I think of Marcel Proust with his epic, In Search of Lost Time, which consists of 7 volumes, but there are 19th century writers who tower over that. 

Anthony Trollope wrote 47 novels. Probably the most prolific writer, maybe ever, though, is Honoré de Balzac. His series, The Human Comedy, consists of around 90 novels. I think that, in the time it took Balzac to write so many novels, I would struggle to read that many. 

And it's not like he was pumping out trash. These are celebrated works of literary genius. They're probably not all equally great, but that's true for every writer ever.