A central theme in “The Purloined Letter” is that of deception versus truth, but the story suggests that these are not easily separable. Openness can be a means of deception, as in the minister’s theft and hiding of the letter, both of which occur in plain sight. Meanwhile, deception or duplicity can at times work to reveal the truth, as in Dupin’s recovery of the letter.

Virtually every character engages in deception. The queen is deceiving the king, and this deception makes her extremely vulnerable to blackmail. Minister D—— perceives this deception when he catches the queen attempting to hide the letter she is reading. He then seizes the opportunity to further his own political interests by stealing the letter from the queen. However, because his power over the queen depends on the letter remaining a secret, he replaces it with a letter he happens to have that is of similar appearance. In other words, while he is openly stealing the letter from the queen, he is aiding her in her own deception by replacing it with a similar letter (and therefore not provoking questions about why someone would want to steal the letter). The minister continues this form of open deception by “hiding” the letter in plain sight when he realizes that the police are searching for it.