Published in 1911, this collection introduces a character who would play an important role through many of the stories -- Flambeau. Flambeau starts as an archenemy in the first few tales and later becomes Father Brown's sidekick. "The Blue Cross," which opens the book, is essentially an introduction to the umbrella-toting detective priest and his eccentric (though logical) methods. "...to hear Father Brown tell it," wrote Bruce F. Murphy in his introduction to "The Innocence and Wisdom of Father Brown," "crime is a manifestation of sin: the criminal must be caught, but he or she must also be saved; the culprit has to be locked up, but the spirit must be freed." Other notable tales include "The Hammer of God," "The Queer Feet" and "The Three Tools of Death."
This second collection, published in 1914, builds on Chesterton's earlier themes of capturing the criminal, yet freeing his soul. It also continues the development of Father Brown as a wise, able detective. "The Absence of Mr. Glass," features a super sleuth (Dr. Orion Hood) who is bested by Father Brown. Hood's methods of deduction should be perfect, but result in very wrong conclusions. Also included are "The Duel of Dr. Hirsch," "The Paradise of Thieves" and the newspaper satire, "The Purple Wig." The criminals in "The Wisdom of Father Brown" are masters of play-acting and must be unmasked by Father Brown. Nine other mysteries round out the collection.
The most striking difference between this 1926 release and previous volumes is the unlikely fame of the title character. Father Brown has gained quite the reputation and uses his crime deduction skills in America. His "incredulity" comes from a string of supernatural mysteries that form the crux of the collection. Notable tales are "The Oracle of the Dog," "The Miracle of Moon Crescent," "The Ghost of Gideon Wise" and "The Resurrection of Father Brown."
Somewhat darker than its predecessors, "The Secret of Father Brown" from 1927 concerns itself with secrets, the nature of sin, and confessions of a different sort. It is in this collection that Father Brown admits to having committed murder. The set includes "The Man with Two Beards," "The Song of the Flying Fish," "The Worst Crime in the World," "Chief Mourner of Marne" and six others. Of note, too, is the appearance of a much matured and settled Flambeau.
Of the eight tales in the final collection, two are standouts: "The Blast of the Book," a mystery about a mystery within a book, and the finale "The Insoluble Problem." "The Insoluble Problem" takes place during an earlier Father Brown investigation with his sidekick, Flambeau. This mystery involves a dead man's body hanging by the neck from a tree with a sword stuck through his body. They must decide which killed the man first: the sword or the hanging.