Albert Campion navigates a series of criminal investigations, ranging from blackmail to espionage, to assist his associates in resolving precarious situations. Campion operates as a gentleman investigator, often utilizing his unconventional social connections to bypass traditional police limitations. He frequently collaborates with Superintendent Oates, balancing his own subtle methods against the formal procedures of the law. The stories are presented as a collection of distinct cases, each focusing on a specific puzzle or social transgression that requires Campion's unique intervention. The world is defined by the social hierarchies of mid-20th-century England, where reputation and discretion are as vital as physical evidence.

Readers frequently highlight the charm of Allingham’s prose and the clever construction of these compact mysteries. Discussion often centers on the evolution of Albert Campion from a caricature into a nuanced investigator who relies on his wits rather than brute force. Critics appreciate the balance between the lighthearted tone of the social interactions and the darker implications of the crimes being solved. The collection is often cited as a prime example of the Golden Age of detective fiction, noted for its sharp characterizations and efficient pacing. Many fans find the inclusion of Campion’s disreputable associates to be a highlight that adds depth and humor to the otherwise serious business of crime detection.