The Mouse That Roared - Leonard Wibberley

Leonard Patrick O'Connor Wibberley (1915-1983) was a prolific Irish-American author, who also wrote under three pen-names. He is best known for his satiric novels about an imaginary country, Grand Fenwick, The Mouse That Roared (5 titles in "The Mouse" serie:
The Mouse That Roared,1955, Beware of the Mouse, 1958, The Mouse on the Moon, 1962, The Mouse on Wall Street, 1969, The Mouse that Saved the West, 1981. Here's the first french edition, illustrated by Siné in 1955.