"The Secret Sharer," which is one of the two short novels in this bi-novel package, taps into that classic theme of a person hiding in a room who does not want to be found. It was first published by Joseph Conrad in 1910. The writing is topnotch, though the means of building suspense by having someone in a room who does not want to be found out handled (much better) by Honore de Balzac in his short story "The Mysterious Mansion" published in 1830 that can be found in my Best Horror Short Stories anthology. Because of this I suggest reading Balzac's classic instead of Conrad's seafaring regurgitation.
On to Conrad's crowning achievement: The Heart of Darkness. The hunt into the heart of a depraved jungle for Mr. Kurtz is one that had few equals up to its publication in 1902. It drew on Conrad's own experience in the Congo and what he saw there. His style of writing is uncomfortable and heated, mimicking the way a person feels on a sultry day. That much is genius and so is one of the first quests in literature for a crazzzzzy person. Francis Ford Coppola got it right in Apocalypse Now and Apocalypse Now Redux:
I need to study this novel, but unfortunately have little time for it at the moment. Sigh. Perhaps when my writing schedule slows down, but there is no end in sight like the darkling jungles as Charles Marlow and his band of sailors troll up the Congo in search the their greatest fears.