* The Robert Burns poem: The title is directly taken from a line in the poem "To a Mouse" by Robert Burns: "The best-laid schemes o' mice an' men / Gang aft agley." This line, meaning that even the best plans of mice and men often go wrong, perfectly captures the tragic fate of the novella's characters.
* The theme of dreams and reality: The title underscores the theme of the novella: the struggle between dreams and harsh reality. The "mice" symbolize the fragility of dreams and the "men" represent the characters who strive for something better but face the limitations of their own circumstances.
* The irony of the dream: The title also highlights the irony of George and Lennie's dream of owning a farm. The "mice" represent the fleeting nature of their dream, and the "men" represent the characters who ultimately fail to achieve it.
Overall, "Of Mice and Men" is a title that succinctly encapsulates the book's major themes, its central characters, and its tragic inevitability.