Judith aka The Naughty Niece
Written by
Leslie Charteris
Copyright 1948
Published as The Naughty Niece in 3 issues of The Saint Detective Magazine (US - Aug. 1957, AUS - Aug. 1957 & UK - Oct. 1957). Also published in the collections and The Second Saint Omnibus.
Judith wants Simon Templar to help stop her uncle from stealing an invention of her father.