The Secret Life of Walter Mitty (1947) Trailer
https://www.youtube.com/watch?v=awthjYwVAr4
The trailer for the original movie.
The Secret Life of Walter Mitty Interview - Ben Stiller
https://www.youtube.com/watch?v=0Oj7sdw3Hjo
An interview with Ben Stiller about the film.
The Secret Life of Walter Mitty
https://www.rollingstone.com/movies/movie-reviews/the-secret-life-of-walter-mitty-102238/
A review of the film in Rolling Stone.