This novel marks MacLean's first foray into the espionage thriller genre, and was inspired by the events surrounding the Hungarian Revolution of 1956.

Michael Reynolds, MacLean's protagonist, is a British secret agent on a wintertime mission inside Hungary at the height of the Cold War.

The plot has the twists, turns, and betrayals in which MacLean specialized, and Reynolds realizes that he has only one chance to escape with Jennings before he is captured and killed by the Hungarian secret police.

The Last Frontier appeared in film under its alternative title of The Secret Ways in an April 1961 release directed by Phil Karlson.

According to an interview with Euan Lloyd in Cinema Retro magazine, producer and star Widmark had disagreements with Karlson, who felt he should use a tongue-in-cheek approach for the story.