"Booby Trap" is a Nero Wolfe mystery novella by Rex Stout, first published in the August 1944 issue of The American Magazine. It first appeared in book form as the second novella in the short-story collection Not Quite Dead Enough, published by Farrar & Rinehart in 1944.

Major Goodwin has been working for Army Intelligence for some time already, and has recently concluded a dangerous mission concerning another problem besides the Nazis: greed by munitions contractors jockeying for post-war power, in the present case by industrial espionage concerning an advanced type of grenade.

Archie has managed to unravel a major piece of the puzzle by a recent mission in the South. Another officer in his unit, Captain Cross, has just been murdered at a New York hotel, and Wolfe is investigating his murder. The remaining members of the unit, plus Wolfe and Congressman Shattuck, have gathered in the New York headquarters for the Army to discuss an anonymous letter that Shattuck, as Chairman of a Congressional war committee, has received about how industrial espionage is compromising the war effort and is therefore a national security matter.

Earlier, Archie was issued one of the advanced grenades in question which he kept in Wolfe's house, mostly as a souvenir. Wolfe does not like it in the house. Before the meeting starts, Archie returns the grenade to the Army at this meeting.

During the meeting, Colonel Rider, one of the officers whose son has just been killed in action in Europe, abruptly announces that he wants to go to Washington to confer with General Carpenter, the Pentagon official in charge of the unit. Rider has brought a suitcase with him, and his highly irregular request is granted. To Wolfe, it is highly irregular that Rider’s secretary is a female sergeant.

As Wolfe and Goodwin return to the building later on the same day, a massive explosion is heard. Colonel Rider is killed. As the building is not owned by Army Intelligence, the NYPD, in the shape of Inspector Cramer shows up, but Wolfe and Goodwin's uncooperativeness, normal as it has been in civilian matters, confuses Cramer now that Goodwin wears an Army uniform, the same that uniform Cramer's son is wearing in Australia.

Wolfe determines that Colonel Rider was murdered. His suitcase was rigged to pull the safety of that new grenade when he opened it the least bit. The remains of the suitcase are damaged from the inside outwards. Wolfe proceeds to invite those few who knew of the new design of grenade to his house. Each entered alone to see objects in the office, including another of the new grenades. Then they are all gathered together in the office, except for that female sergeant, where drawers are opened in turn, seeking the misplaced grenade. The Congressman reveals himself as the killer by his reactions to the trap set by Wolfe. He has murdered two soldiers, and is heavily involved with corruption during the war.

Wolfe and Archie drive him to a park to end his own life, rather than charge him in court in war time.