"The Mouse That Roared" is a satirical novel by Leonard Wibberley, published in 1955. The story follows the tiny European principality of Grand Fenwick, which declares war on the United States in a desperate attempt to gain foreign aid. The plan backfires when they accidentally win the war, leading to unexpected consequences. The novel explores themes of power, politics, and the absurdity of war. It humorously critiques the dynamics between small nations and superpowers, highlighting how even the smallest entities can have a significant impact on global affairs. The book has been adapted into a film and remains a classic in political satire.