The kidnapped child is Viola Throckmorton. In the novel, her name was Viola Inselheim, daughter of a prominent Jewish businessman. This is one of several alterations of ethnicity in the film adaptation. "Dutch," a gangster, becomes "Hutch" in the film. This was a possible reference to New York mobster Dutch Schultz - born Arthur Simon Flegenheimer - who was killed in 1935.
The first of nine classic RKO movies featuring Simon Templar, The Saint.
At one point, Louis Hayward as the Saint refers to himself as "a lone wolf." In 1954, he would play in The Lone Wolf (1954), a TV series.
Lipke's taxi license (which expires on March 31st 1942) is, perhaps implausibly, numbered 12345.
This film was popular at the box office, making RKO a profit of $195,000 according to studio records.