Sir Walter Scott by Henry Raeburn.

From the Wikipedia article on Kenilworth by Walter Scott:

In January 1820 Archibald Constable and John Ballantyne concluded an agreement to act as joint publishers of Kenilworth, but Scott had still to complete The Monastery and write its sequel The Abbot which kept him occupied until August, so that Kenilworth had to wait until September. Writing then progressed steadily, and the new novel was completed on 27 December.

From the Wikipedia article on Finnegans Wake by James Joyce:

For the next few years, Joyce worked rapidly on the book, adding what would become chapters I.1 and I.6, and revising the already written segments to make them more lexically complex.

James Joyce by Djuna Barnes, 1922.