Middle-aged CPA Paul Benjamin lives in Manhattan with his wife Esther in an apartment close to their daughter Carol and her husband, Jack Tobey.

Paul is a staunch liberal, volunteering his time to civic organizations and trying to rationalize the crime and misery he witnesses on a daily basis.

He refuses to move out of the city, explaining that while the suburbs might be safer and cleaner, he cannot leave New York after having lived there his entire life.

After his wife's funeral, Paul refuses to leave his apartment, has new locks put on the doors, and starts carrying a club made from a sock stuffed with quarters in his pocket.

He sleeps with Shirley, a woman whom he meets in a bar, visits a sporting goods shop, purchases a revolver and smuggles it back into New York along with a large stash of ammunition.

He then purchases a jacket, hat, and gloves and starts looking for criminals, deliberately presenting himself as a harmless, affluent old man in order to attract attention.

A feature film based on the novel was made in 1974, starring Charles Bronson in the lead role as Paul Benjamin, the surname being changed to Kersey and his profession being an architect, and directed by Michael Winner.

[2][3] A 2018 remake, starring Bruce Willis in the lead role, also named "Kersey" and profession being changed to surgeon, was by Eli Roth.

He described it as "incendiary", because he felt upset that the film's audience was encouraged by the violence and vigilantism, despite the story being against both topics in his book, in which Charles Bronson agreed with.