Fictional character created by English author Oliver Strange
James Green aka "Sudden" is a fictional character created by an English author Oliver Strange in the early 1930s as the hero of a series, originally published by George Newnes Books Ltd, set in the American Wild West era. Oliver Strange died in 1952, and the series was revived by Frederick H. Christian in the 1960s. Christian classified the books as "Piccadilly westerns", that is books written by English authors, simply drawing on the conventions the genre, with no first hand experience of America. The Sudden books are among the earliest and best-loved of the type.
https://en.wikipedia.org/wiki/Sudden