Balthazar B, a shy and wealthy young man, navigates the complexities of post-World War II society alongside his chaotic companion, Beefy. Raised in privilege and later sent to a British boarding school, Balthazar finds his quiet existence disrupted by the influence of his friend, Beefy. Together, they transition to Trinity College, Dublin, where their pursuit of academic and romantic interests leads to a series of social complications. The narrative follows their development through a period of significant personal and historical change, utilizing a prose style marked by rhythmic, idiosyncratic energy. The story examines the tension between Balthazar's reserved nature and the uninhibited behavior of his peer.

Readers and critics frequently observe that the novel captures a specific brand of mid-century malaise through its eccentric characterizations. Discussion often centers on the balance between the protagonist's inherent shyness and the disruptive, often comedic, influence of his companion. Many highlight the author's unique linguistic style, which relies on a rapid-fire delivery that keeps the pacing brisk despite the introspective nature of the plot. The work is widely regarded as a significant entry in the author's bibliography, noted for its blend of sincerity and satirical wit. Readers often find the depiction of university life in Dublin to be a standout element that grounds the more whimsical aspects of the narrative.