Albert Campion makes his first appearance at the Black Dudley dinner-table [in The Crime at Black Dudley (1929), published in the United States as The Black Dudley Dudley Murder]….

[Although] his persona is decidedly comic at first, there is yet implicit in the absurdity something of the seriousness of his later self….

Campion's eccentricities save him, in this first book, at least, from the danger of conventionality. There is, after all, nothing exceptional about his heroics at Black Dudley; the courage, the resilience, the resource, constitute the stock-in-trade of the most standard model of fictional adventurer. The special interest of Campion is that we do not at first know how to take him—that he proves, for instance, to have an "agility and strength altogether surprising in one of such a languid appearance": and it is this capacity for "surprising" that makes him, from the first, an intriguing figure...