The book is presented as a manuscript written by its protagonist, a middle-aged man named Harry Haller, who leaves it to a chance acquaintance, the nephew of his landlady. The acquaintance adds a short preface of his own and then has the manuscript published. The title of this “real” book-in-the-book is Harry Haller’s Records (For Madmen Only).
As the story begins, the hero is beset by reflections on his being ill-suited for the world of everyday, regular people, specifically for frivolous bourgeois society. In his aimless wanderings about the city he encounters a person carrying an advertisement for a magic theatre who gives him a small book, Treatise on the Steppenwolf. This treatise, cited in full in the novel’s text as Harry reads it, addresses Harry by name and strikes him as describing himself uncannily. It is a discourse on a man who believes himself to be of two natures: one high, the spiritual nature of man; the other is low and animalistic, a “wolf of the steppes”. This man is entangled in an irresolvable struggle, never content with either nature because he cannot see beyond this self-made concept. The pamphlet gives an explanation of the multifaceted and indefinable nature of every man’s soul, but Harry is either unable or unwilling to recognize this. It also discusses his suicidal intentions, describing him as one of the “suicides”: people who, deep down, knew they would take their own life one day. But to counter that, it hails his potential to be great, to be one of the “Immortals“.