Like Freytag and Paul Heyse, Friedrich Spielhagen was chiefly concerned, in his novels, with defining the warring elements of German character and the opposing springs of German action in the period before and after the revolution of 1848.
Like Freytag and Heyse, Spielhagen saw clearly the dangers that threatened the country, politically, religiously and morally from a reactionary aristocracy; like Heyse and unlike Freytag he saw the hope of the nation in the spread of an enlightened democracy rather than in a spiritual renaissance of the ruling classes.
The hero of Problematische Naturen, Oswald Stein, is the mouthpiece for Spielhagen's revolutionary social theories.
He is modeled after those characters of whom Goethe wrote “There are problematical natures that do not fit into any situation and who remain always unsatisfied.
For such a philosophy, there could be no better historical background than the Germany of 1848 and after, and Problematische Naturen with its sequel Durch Nacht zum Licht (1862), — although it squanders material for half a dozen novels, idealizes Teutonic morbidity, and forsakes art for tendency, — tells with remarkable vividness the story of the men and women who lived and thought and fought for freedom in Germany's day of hope.