Sleuth, like its own Milo Tindle, disguises itself and purports to disapprove of the old-fashioned parlor room murder mysteries popularized by such masters of the genre as Agatha Christie, Dorothy L. Sayers, and Sir Arthur Conan Doyle. Also like Milo, the play indulges in flamboyant and elaborate tricks used so successfully by the past masters. In so doing, Sleuth unmasks itself for what it really is: Anthony Shaffer’s backhanded, revitalized homage to the supposed outdated parlor room puzzler. While it is lambasting the genre for being sterile, overly intellectual, and bloodless, Sleuth is also lauding the genre for its playful plot twists, elaborate deceptions, and unabashed ability to entertain.

Andrew Wyke is the personification of the genre itself. He is quick-witted, theatrical, and obsessed with elaborate plot schemes. His speech is lively and rich with horrible puns and allusions to his beloved literary compatriots as well as his own works. He is also, like the genre, extremely class-conscious, intolerant of people whom he deems not part of his insulated, aristocratic world. Milo, young, vigorous, and handsome, the son of an Italian immigrant, is a threat to Andrew. He represents everything that Andrew is not. As he tells Milo just before he shoots him in act 1:I hate your smarmy, good-looking Latin face and your easy manner. . . . I hate you because you are a culling spick. A wop—a not one-of-me. Come, little man, did you really believe I would give up my wife and jewels to you? That I would make myself that ridiculous?

Milo represents the world of flesh and blood reality. His world is in direct conflict with Andrew’s universe of intellectual games, contrivances, and manipulation. However, both worlds are potent ones. It is obvious that Milo is at first awed by Andrew’s passionate love for games-playing. Although Milo does not agree with Andrew’s assertion that the world of detective fiction is superior to detective fact, and that the detective story is “the normal recreation of noble minds,” he still cannot resist becoming caught up in Andrew’s frenzied enthusiasm for games-playing. After the games turn deadly, however, Milo’s admiration turns to revulsion. In the end, after he has taken his revenge on Andrew by beating him at his own manipulative games of deceit and humiliation, he tells Andrew:Take a look at yourself, Andrew, and ask yourself a few simple questions about your attachment to the English detective story. Perhaps you might come to realize that the only place you can inhabit is a dead world. . . . It’s a world of coldness and class hatred, and two-dimensional characters who are not expected to communicate; it’s a world where only amateurs win, and where foreigners are automatically figures of fun. To put it shortly, the detective story is the normal recreation of snobbish, outdated, life-hating, ignoble minds.

In the end, it is Milo’s world of facts, of real police detectives and real death, that destroys Andrew’s world of charades and betrayal. Or so it seems. For the main, overriding theme of Sleuth is the beguiling fascination this artificial world of games has on the world of fact. The audience is held spellbound by the play’s string of deceits, fake murders, disguises, and manipulative acts. Sleuth therefore proves that Andrew’s world is hardly dead, and that with a few modifications the old-fashioned parlor room puzzler can still pack quite a dramatic punch.

Deception
The elaborate game playing that takes place in Sleuth is indicative of its most important theme: deception. Milo's "crime" against Andrew starts with an act of deception, that is, having an affair with his wife. To teach Milo a lesson about trying to fool a master at the art of deception, Andrew devises his plan. He succeeds in terrifying and humiliating Milo. By virtually holding Milo's life in his hand, Andrew demonstrates that Milo is in his control, despite the affair with Marguerite.

Milo responds in kind. He devises two plots of his own. First, he makes Andrew think that he will go to jail for murdering Milo, and then he makes Andrew think he will go to jail for murdering his girlfriend, Tea. The one deception following the other thoroughly convinces Andrew that he will go to prison for a crime he did not commit.

As Milo's true game-playing ability is revealed, Andrew feels that he has found an equal game player. He proposes they stay together and continue to play these games. Milo refuses to live in a world where puzzling another person—an act of deception—is the main goal. Both men end the play by committing their first honest acts: Andrew fatally shoots Milo, just as he said he would; and the police come to Andrew's home, based on Milo's report, just as Milo predicted.

The prevalence of deception is reinforced by other elements of the play. For instance, Tea's agreement to help Milo deceive Andrew plays a crucial role in Andrew's belief of the story that he had originally ridiculed. Disguises also play an important role. Milo dresses up as a clown, at Andrew's behest, when he "breaks in to the house," and, indeed, he is at the moment being played for a fool. In act 2, Milo disguises himself as Inspector Doppler and thoroughly deceives Andrew.

Revenge
Both men devise their plans to exact revenge on the other. Andrew claims to merely want to play a game, but in truth, he is exceedingly angry that Andrew has dared to take away his wife, even if he does not want Marguerite for himself Further, Milo mocks what Andrew holds most dear, a world in which he has virtually lived his life—the "dead world" of the classic detective story. Andrew, growing old and impotent, also resents Milo's youth and virility.

For his part, Milo feels compelled to come up with his game to get revenge. He had gone to the police with the story of what Andrew did to him, but the police didn't really seem to believe him despite the evidence of a powder burn from the gun on his hand.

Theft
The theme of theft has both an actual and a symbolic role in Sleuth. Milo has stolen away Andrew's wife. In his fantasy, as well, Milo steals Andrew's mistress, Tea. Andrew's plan to get back at Milo involves the faked theft of jewels. The final confrontation between the two men revolves around the purported theft of Marguerite's fur coat. Because of these instances, the theme of theft takes on an ironic slant. Shaffer exploits this irony in his choice of dialogue. For instance, Andrew tries to explain to Inspector Doppler what happened between him and Milo as a game called Burglary.

Class and Race
Andrew demonstrates class and racial prejudice. He looks down on Milo for many reasons. Milo is one-quarter Jewish and half foreign—the child of a farmer's daughter and an Italian watchmaker. Further, Milo holds a lower socioeconomic standing. Andrew thinks that these characteristics make Milo his inferior. Milo understands the prejudices that people such as Andrew hold. He acknowledges that his father changed his named from Tindolmi to Tindle when he moved to England; otherwise he would have been branded a dumb immigrant.

Right before he "kills" Milo, Andrew openly denigrates him. Several times he calls him a wop. He refers to his "smarmy, good-looking Latin face" and dubs him "a not one-of-me." When Inspector Doppler comes to "investigate" Milo's "murder," Andrew explains that he was angry that Milo dared have an affair with his wife. It would be all right to lose to a "gent,'' he claims, who plays by the same rules—that is, the English upper-class rules—but not to a "flash crypto Italian lover.''