Karl Riha is a German author and literary scholar.

Karl Ristikivi was an Estonian writer. He is among the best Estonian writers for his historical novels.

Johann Karl Friedrich Rosenkranz was a German philosopher and pedagogue.

Karl Rudolf Hagenbach was a Swiss church theologian and historian. He was particularly interested in the Protestant Reformation and its figures.

Karl Sabbagh is a British writer, journalist, television producer, and convicted sex offender. His work is mainly non-fiction: he has written books about historical events and produced documentaries for both British and American broadcasters.

Karl Scheffler was a German art critic and publicist.

Karl Schenkl was an Austrian classical philologist.

Karl Schlögel is a noted German historian of Eastern Europe who specialises in modern Russia, the history of Stalinism, the Russian diaspora and dissident movements, Eastern European cultural history and theoretical problems of historical narration.

Karl Schönherr was an Austrian writer of Austrian Heimat themes.

Karl Schroeder is a Canadian science fiction author and a professional futurist. His novels present far-future speculations on topics such as nanotechnology, terraforming, augmented reality, and interstellar travel, and are deeply philosophical. More recently he also focuses on near-future topics. Several of his short stories feature the character Gennady Malianov.