Nabokov has called The Government Inspector the product of Gogol's fancy in which his private nightmares are peopled with its own incomparable goblins. Gogol combined a love of the grotesque with the keenest power of observation. Is Khlestakov, the St Petersburg clerk mistaken for a high official, man's corrupt conscience made flesh? Or is this play a scathing portrait of Russian corruption?
The news that a government inspector is about to arrive incognito for a 
secret investigation reveals the depths of corruption and decay in a 
small provincial town. 
The top officials, led by the mayor, react in
 shock, and a flurry of activities follows to cover up their various 
abuses and to clean up the city. The local judge usually accepts 
bribes in the form of greyhound pups; the physician of the hospital 
doesn't bother to cure the patients entrusted to him; the school 
superintendent presides over a bunch of drunks; the postmaster always 
opens everyone's letters; and the mayor pockets public money, allows 
violence among the constabulary and lets rubbish accumulate throughout 
the town. 
Then it is discovered that a suspicious young man from St 
Petersburg has arrived already two weeks ago and is staying in the 
town's inn. The dignitaries immediately conclude that this must be the dreaded 
government inspector. In reality, it is Khlestakov, an impoverished 
young civil servant from the capital on his way to his parents' estate -
 he has been stalled in the small town because he has run out of money. He has not paid any of his bills, but does everything on credit. 
So the mayor and his cronies
 confuse this comical and insignificant dandy with the much-dreaded 
inspector. Soon the two parties meet. Khlestakov thinks he is about to be arrested 
because of the unpaid bills, and becomes furious. He shouts and 
complains that the food does not taste good anyway. The mayor is 
completely intimidated by this outburst and even more convinced that he 
is dealing with a real top government official. He calms Khlestakov down and
 when hearing he has run out of money, quickly slips him 400 rubles as
 a bribe. Khlestakov from his side at first is surprised at how very good-natured and 
generous the people of the town are, but then realizes that they must be mistaking him for someone 
else. 
Eager to impress, the town's notables hope they’ve done enough to cover up the shoddy operation of their school, hospital, police station and court house – the latter was operating as a hunting lodge until they heard of the inspector!  Accepting generous bribes from the town officials, Khlestakov leaves them under their delusion and spins elaborate yarns of his life as a high-ranking government official. The Mayor offers his house for Khlestakov to reside in. The visitor accepts and starts flirting outrageously with Maria and Anna, the Mayor's wife and daughter. Getting carried away, Khlestakov even proposes to Maria.
Fortunately,
 on the advice of his more sober servant, he manages just in time to flee the city. This happens moments before the 
dignitaries, to their dismay, intercept a letter revealing Khlestakov's 
true identity. As the notables argue, the play ends 
with the announcement that the real Government Inspector is in town and that he  immediately wants to speak to the mayor, whereupon the characters 
freeze on stage.
Based on an anecdote allegedly told to Gogol by Aleksandr Pushkin, this is a satire about human shortcomings, greed, stupidity and political corruption. The publication caused a stir and the play was adapted several times to get it performed effectively. 
English translation at project Gutenberg. I have read the translation by Christopher English in Oxford World's Classics ("Plays and Petersburg Tales").
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