Although I haven't featured anything by him on the blog, Kafka is one of my favorite authors. Perhaps this is obvious.
I'll be searching for a copy of Jean-Michel Folon's illustrated Metamorphosis (1973, Olivetti of Italy) for years to come. I scanned these from an old Japanese magazine.
In his introduction to Metamorphosis and Other Stories (Penguin, 2007; buy the deluxe version with the Sammy Harkham cover before it disappears), Michael Hofmann writes of:
...Kafka's suggestion as to how his story might be illustrated, if it had to be illustrated—not, pace Nabokov, with an entomologically or coleopterically correct beetle... but with a picture of a man lying in bed.