Nathan is a scientist, erudite, clever and charismatic, Sophie is beautiful, musical and hopelessly in love with Nathan, who she views as a saviour, while Stingo is young, a virgin, and (despite his army service in the Second World War) surprisingly innocent. What starts off as a happy relationship between three close friends rapidly becomes darker as Nathan's behaviour becomes ever more erratic. As Nathan slides into drug abuse and paranoid schizophrenia, Sophie starts to reveal to Stingo her own background, and the choice that has haunted her life.
I must admit to a problem here - I knew from the outset (probably from seeing snippets of the film) what Sophie's ultimate choice was, and it may be that because of this I read the whole book slightly differently. Sophie, a Pole, was imprisoned in Auschwitz when she was caught smuggling a piece of ham into Warsaw (so establishing her non-Jewish credentials). From an anti-Semitic background, and not afraid on occasion to use this anti-Semitism to try to get a better life for herself once in the camp, Sophie is faced with choices throughout her life. The ultimate choice however will lie for her on the ramp at Auschwitz when she is forced to decide which of her children should go to the gas chamber.
William Styron was not scared of controversy, a gentile writer with a gentile concentration camp heroine provoked dissent in some quarters. An earlier novel by Styron about Nat Turner, the leader of a slave rebellion in Virginia upset many African-Americans, though writers such as James Baldwin praised it. Styron aimed in Sophie's choice to show that although the camps were set up to provide the "Final Solution" for the Jews of Europe, they also swallowed anyone who offended the death machine that was the Third Reich - gypsies, people from nations that the Nazis believed failed to stand up to their genetic standards, homosexuals, intellectuals - even Sophie's father, a monstrous anti-Semite, will ironically end his days in Sachsenhausen.
Sophie's everyday life choices become exaggerated as she is forced to make unspeakable choices in the death camps. Ultimately the novel is about the evil of the Nazis, and the total evil of the death camps; but it's also about the choices that people make every day, the choices that can lead to a work of art, or great kindness, or hideous evil. Juxtaposed against Sophie's terrible tale are the good things in life - love, sex, art, music, family. But all of these also have their perversions - from Stingo's ill-fated attempts to lose his virginity, Nathan's love for Sophie but also his descent into madness in which his love becomes jealously twisted, even (cleverly) to the corruption of music played by the Auschwitz camp orchestra on the doorstep of Hell. There is also Sophie's own love for her father, confused though it is by her hatred of his political beliefs.
The novel doesn't always work, some characterisations are flimsy, some plotlines (including a few important ones) don't altogether make sense. But whatever you think about the background of Sophie, it is impossible not to be moved by the searing relentless cruelty that throbs at the heart of Sophie's choice. It is a stunning novel, appalling, sad and impossible to put down till you have turned the last page.
For more responses to the novel see The 'grey zone' in William Styron's Sophie's Choice, and The Wall Street Journal with Lee Childs.