Tartuffe is an extremely entertaining, satirical play, written by Moliere, a famous playwright with a flair for comedy--with the purpose of pointing out the foibles of society. In this case, Moliere's intention is to highlight the hypocrisy of French society regarding its tendency to preach religious and moral standards to others, while disregarding those same standards for themselves.
In this play, Tartuffe is a charming con man. He makes the acquaintance of a very wealthy man, Orgon. Without much thought, Orgon takes Tartuffe into his home as a guest although Tartuffe is a stranger.
Tartuffe acts like a very holy and religious man. Orgon, taken in by this charlatan, asks Tartuffe to reside with the family as a moral guide, and he offers Tartuffe the best of everything, including his attention and affection--even better than what Orgon's family receives. Orgon even goes as far as to plan Tartuffe's marriage to Orgon's daughter.
Although he is warned by others that Tartuffe is a fraud, Orgon can see no fault in Tartuffe until Orgon catches the con man making advances toward his own wife.
However, Tartuffe is not wholly to blame. Moliere structures the play around Tartuffe who represents the hypocrisy of French society, as Moliere sees it. (The Church banned the play for several years.) However, Tartuffe is simply the foil used to expose Orgon, who represents that portion of society that is gullible and foolish. Had Orgon not been so easily duped, if he had been able to consider the advice of those around him in seeing Tartuffe more objectively, Tartuffe would certainly never have been allowed to have his way in Orgon's home. It is only when Orgon can see for himself (another character of human nature) that the foolish man finally believes what others have been trying to tell him.
In the meantime, as he tries to throw Tartuffe out, Tartuffe threatens revenge by taking secret documents Orgon had told Tartuffe about, to the King. It looks like Orgon is about to lose everything for having foolishly taken Tartuffe into his confidence, but at the last minute, the King's men arrest Tartuffe for other crimes he has committed. The play ends as Orgon tries to put his life back in order.
Orgon has learned that although Tartuffe is to blame for specific misdeeds against Orgon and his family, that Orgon himself is guilty of letting Tartuffe into his home and putting those closest to him in jeopardy by placing Tartuffe above them in his heart and mind.
Tartuffe represents false religious piety. He is a con man of the highest order. He successfully hoodwinks Orgon into thinking that he is what the family needs to return them to their religious values that they seemingly have lost. Of course, the family resents Tartuffe's intrusion and recognize him for the fraud that he is.
But every con man needs a victim. This victim is Orgon (and to a lesser extent Madame Pernelle). Orgon is willing to believe a stranger over the concerns of his own family. He is taken in by a show of piety rather than true piety. He is unable to distinguish true morality from fake. He is willing to sacrifice his daughter against her wishes to a marriage that will obviously make her unhappy. He is so convinced that he is right that he has little care for the feelings of those he should most be concerned about. His obsession with Tartuffe costs him his wife (who is put into the lusty Tartuffe's watch), his daughter (whom Orgon orders to marry Tartuffe), his son (whom Orgon disowns), and his brother-in-law (who walks out of the house without his wise counsel being heard) untill all is restored by the end of the play.
Orgon for being such a dupe is as least as culpable as Tartuffe, maybe even more so.