** spoiler alert ** 
 In many ways, it seems to be a nearly perfect story in terms of construction and balance - the major themes of the story can be viewed through multiple characters and circumstances, and the beginning-middle-end all form a cohesive snapshot of people at a particular time. Everything is so beautifully and clearly described that it's easy to picture it all unfolding. 
 George and Lennie are terrific together. I love the fact that George is, on one hand, caring and responsive, while on the other hand he says some fairly mean (or at least cranky) things. I'm not proud to admit this, but I just wouldn't have the patience to deal with Lennie day in and day out, so I love the fact that George has this ongoing dialogue of frustration while he does what he knows he has to do ... take care of Lennie. Lennie also provides something George needs: a sounding board who will listen to him and, to some extent, an excuse for not achieving his dream of having his own farm. 
 For his part, Lennie is such an innocent and would be fine if they could just get him to realize his own strength. His childlike behavior and sweetness compensate for his lack of intelligence and he is always honest and open. This friendship has such wonderful dimension - part classic friendship, part caregiver/receiver relationship and part something else that's hard to define but is mutually beneficial. Without Lennie, George would be a meaner man; without George, Lennie would be ill-treated. 
 The theme of self-control is interesting. Lennie of course needs to control his physical strength because once he releases his anger, he can't control it. Curley needs to learn self-control because his temper and need to show both his physical strength (despite his short stature) and his power (that comes from being the boss's son) can get him into trouble. He is such a vile person that he will end up coming to a bad end if he doesn't find some gentleness or positive approach to life. Those who have self control - Crooks, Slim, George (at least to some extent) and others - are shown to be stronger for it. 
 Curley's wife, though presented as a tart with a sharp tongue, is a very lonely young woman whose life cannot be easy. She also needs to learn to self-control. In her case, she needs control the desire to flaunt herself - not only because she could put herself in some danger but also because she doesn't seem to realize that the more she does it, the more she pushes others away. The very company she seeks is thwarted because the men see her as a threat to their jobs and to the bunkhouse routine. The treatment of women is always interesting in older stories. In this case, she has no name of her own, which services two purposes: to show her as Curley's property and to show her from the men's perspective as someone they don't want to know better. 
 Loneliness is a key theme as well. The men are surprised that Lennie and George travel together because it is unusual for men to form these bonds. Everyone is alone, even when surrounded by people. Poor old Candy is seeing the consequences of this lifestyle - he is reaching the end of his usefulness. What will happen to him when he can no longer pull his own weight - when he is like the old dog that no one wants to have around? 
 The last scene is just so sad. And, yet, how else could it play out - at that time and place? Perhaps today, Lennie would have gotten the help he needed or at least a fair trial.