Some of the important themes in 'Of Mice and Men' include friendship, struggle, and the quest for the American dream.
Friendship is an important theme in Of Mice and Men.
Interpretation #1: George and Lennie demonstrate that no matter how bad things get, friendship makes life worth living. George's selfless service to Lennie and Lennie's childlike innocence give their friendship special meaning. George's final act of friendship is allowing Lennie to see his dream before shooting him in the back of the head.
Interpretation #2: Friendship is useless in George and Lennie's world. Lennie is nothing but a handicap to George's success. Lennie should have been shot long ago.
Interpretation #3: George and Lennie's friendship cannot survive the brutal world in which they live, a world in which goodness is stamped out by injustice and oppression. George has only one option after Lennie accidentally breaks Curley's wife's neck, and their friendship must be severed.
Interpretation #1: George's struggles make him the novel's hero. He overcomes an oppressive society by remaining loyal to his helpless friend. Other heroes in the novel include Slim, who has become the leader of the ranch hands, Candy, for persevering in his old age, and Crooks, for overcoming his crippling injuries and racism while maintaining his dignity.
Interpretation #2: Life's struggles defeat George, Lennie, Crooks, Candy, and Curley's wife. George wastes his life in cathouses and bars; Lennie is too stupid to do anything; Crooks is defeated by racism; Candy, after a life of struggle, is old and useless; Curley's wife has had her dreams crushed and remains nothing more than a tart. The only individual that wins is Curley, the privileged oppressor.
Interpretation #3: George overcomes the evil in his society by making sacrifices for Lennie. Other than Slim, George is the only character who acts nobly and not defeated by the end of the novel.
The American Dream
Another interesting theme running through the book is the pursuit of the American Dream.
Interpretation #1: Corporations are bad. Landowners are bad. Capitalism is bad. Rich people are bad. Migrant workers are noble.
Interpretation #2: Of course George doesn't achieve the American Dream--he spends all his money on booze and prostitutes.
Interpretation #3: The Declaration of Independence states that all men are created equal and endowed by their creator with unalienable rights, including life, liberty, and the pursuit of happiness. These rights embody the American Dream. The question that must be answered is do George and Lennie possess these rights in the context of their society?
Let's begin with life. Lennie loses his right to life, unfairly. He obviously needs help. He cannot survive in the world due to his mental handicap. For this reason, Lennie does not have his right to life upheld.
There is, however, nothing preventing George from enjoying the right to life. Both men have the liberty to dream and work where they can find it; their liberty, however, is limited by two things:
(1) outside forces, often hostile, which dictate to them what they can and cannot do;
(2) George's vices, without which George would be able to save enough money to buy his dream property, assuming of course this property exists. Both men are free to pursue, happiness, symbolized by their dream of owning their own piece of land.
In short, George prevents George from achieving his dream. No matter how tough things are and no matter how much we admire his loyalty to Lennie, we cannot overlook his faults. Lennie, on the other hand, is deprived his rights by unfair mob rule and a mentor who squanders his opportunity through vice.