"The Roman Hat Mystery: A Problem in Deduction" by Ellery Queen is a detective novel written in the early 20th century. It presents a classic closed-circle murder set in a Broadway theatre, where Inspector Richard Queen and his son Ellery investigate the poisoning of a notorious lawyer during a performance. The case hinges on rigorous deduction, suspiciously empty seats, and a missing tophat that turns into the puzzle’s signature clue. The opening of the novel frames the story with a foreword by a friend who recounts retrieving Ellery’s manuscript and sketches the father–son team’s complementary talents. The scene then shifts to the Roman Theatre during the gangster play “Gunplay,” where a commotion reveals an audience member—Monte Field—dead in his seat. Officer Doyle locks down the house; Inspector Queen and Ellery arrive, establish a tight time window (last seen alive around 9:25, found dead about 9:55), and note seven sold-but-empty nearby seats and a conspicuously missing top hat. Early inquiries produce a half-empty ginger-ale bottle (procured by orangeade boy Jess Lynch for Field), a flask, evidence pointing to fast-acting poison, and no gun or stab wound. Usher and doorman accounts suggest no straightforward comings and goings, while a known crook, “Parson” Johnny Cazzanelli, is caught trying to slip out, and Field’s former partner Benjamin Morgan is identified in the audience. The police begin collecting names and ticket stubs, order a painstaking search, and flag the missing hat as a critical lead, with a lexicon of characters and a theatre map signaling a fair-play, clue-driven investigation. (This is an automatically generated summary.)

The Roman hat mystery : $b A problem in deduction