Leonard Patrick O'Connor Wibberley (1915 –1983) was a prolific and versatile author. Born in Dublin, Ireland, he spent most of his life in the United States. He published, under his name and also three pen-names, over one hundred books and is probably best known for four satirical novels about an imaginary country Grand Fenwick--particularly for the first of these, The Mouse That Roared which was made into a feature film starring Peter Sellers.
Wibberley's adult and juvenile publications cut across the categories of fictional novels, history and biography. He also wrote short stories (several published in The Saturday Evening Post), plays and long verse poems. He produced more than fifty juvenile books, for example (with Farrar, Straus and Giroux) the seven-volume Treegate series of historical fiction, which takes place during the American Revolutionary War and the War of 1812, and a four-volume life of Thomas Jefferson. Two of the Treegate volumes can be regarded as HNF.