Here is a PDF file I scanned of the 1890 Knut Hamsun essay, "From the Unconscious Life of the Mind." It was very hard to find, for reasons I will get into briefly. The main reason was because he was a Nazi-sympathizer during WW2 and an admirer of Hitler. I'm not an expert on the man and his politics, but I'm not going to bother rationalizing or softening his views because they are horrific. It would be so much easier for me if he was just deeply misunderstood because I love his writing, but there's just no way around it.
So anyway, he's not a person people want to promote or have admired. I've read articles that reference the essay with a few quotes, but the essay does not exist for sale anywhere on this planet. I tried to find links to it online, but it just wasn't there. It was not at any of my local libraries either. One librarian said that only a few places in the world have it available for interlibrary loan, and only 250 copies were printed of the essay, as a chapbook.
So I got it from a library in Kentucky and scanned the essay (it's only a few pages).
To summarize Hamsun's writing style, it relies less on traditional conflict and plot, and more on the subtle observations of human psychology, emotion, and behavior. He has strongly influenced other great writers such as Kafka, and Hemingway once said, "Everything I learned about writing I learned from Hamsun."
Here are my two favorite passages:
"There can be completely inexplicable states of perception... all phenomena which have the very greatest significance, but which a coarse and simple marketplace mentality cannot comprehend. They are often too transitory to be grasped and held securely, they last a second, a minute, they come and go like flashes; but they leave a mark, make an impression before they disappear."
And my favorite:
"We would experience a little of the secret movements which are made unnoticed in the remote places of the soul, the capricious disorder of perception, the delicate life of fantasy held under the magnifying glass, the wanderings of these thoughts and feelings out of the blue; motionless, trackless journeys with the brain and the heart, strange activities of the nerves, the whispering of the blood, the pleading of the bone, the entire unconscious intellectual life. And then there would be fewer books with the cheap, external psychology which never unravels a mental state, never dips down into mental examination."
The second passage sums it up best. Here is a copy of the essay. I hope you enjoy!