Overview
The 39 Steps calls for the entirety of the 1935 adventure film The 39 Steps to be performed with a cast of only four.
One actor plays the hero Richard Hannay, an actress plays the three women with whom he has romantic entanglements, and two other actors play every other character in the show: heroes, villains, men, women, children, and even the occasional inanimate object.
This often requires lightning-fast quick-changes and occasionally for them to play multiple characters at once.
Thus the film’s serious spy story is played mainly for laughs, and the script is full of allusions to (and puns on the titles of) other Alfred Hitchcock films, including Strangers on a Train, Rear Window, Psycho, Vertigo, and North by Northwest.