It directly challenges the audience with alienating techniques. For example, slogans are projected on the back wall and the characters sometimes carry picket signs, or stand at times with their backs to the audience. The score, by Kurt Weill, was deeply influenced by jazz. The title song, Die Moritat von Mackie Messer, was adopted by Louis Armstrong as the loosely translated Mack the Knife. It was also a pop hit for Bobby Darin.
The central character, MacHeath (Mack the Knife), a highwayman of some renown, marries Polly Peachum. This displeases her father, Jonathan Peachum, who controls the beggars of London, and he endeavours to have MacHeath hanged. This is somewhat complicated by the fact that the chief of police, Tiger Brown, is an old friend of MacHeath's. Peachum exerts considerable political influence, and eventually MacHeath is arrested and imprisoned, escapes, then imprisoned once more. At the point of execution, he is pardoned and given a baronetcy.
The play challenges conventional notions of property. It asks the central rhetorical question, "Who is the bigger criminal: He who robs a bank or he who founds one?"
Interestingly, when this play was translated into French, it was given a name in French that means "The Fourpenny Opera", L'Opéra de quat'sous. Threepence was a common denomination in British coinage having no direct equivalent in France.