I found that the themes of loyalty, obligation and love were paramount. George would not allow the mob to slaughter Lennie, even as Candy's "right" to put down his own dog was usurped. George's love for Lennie obliged him to ensure that Lennie died humanely, in the place where his memory of the dream farm was considered. Steinbeck often intertwines social hierarchy with the sense of irrevocable "fate;" man's choices within a setting of limited free will/destiny. Archetypal stereotypes of goodness and evil are prevalent themes in his and other writers of the time period, and are always relevant, because such traits are present in all of us regardless of time period.