Of Mice and Men is a 1939 American drama film based on the 1937 play of the same name, which itself was based on the novella of the same name by author John Steinbeck. The film stars Burgess Meredith, Betty Field, and Lon Chaney Jr., and features Charles Bickford, Roman Bohnen, Bob Steele, and Noah Beery Jr. The film tells the story of two men, George and his intellectually disabled partner Lennie, trying to survive during the dustbowl of the 1930s and pursuing a dream of owning their own ranch instead of always working for others. Starring in the lead roles were relative Hollywood newcomer Burgess Meredith as George and veteran actor Lon Chaney Jr. (the son of famed silent film actor Lon Chaney) as Lennie. Chaney had appeared in more than 50 films by that point in his career, but Of Mice and Men was his first major role. Betty Field's role as Mae was her breakthrough role in film.

References:
https://en.wikipedia.org/wiki/Of_Mice_and_Men_(1939_film)