One of the main themes is reflected in the title, The Outsiders. Ponyboy and his brothers are lack the "normal" comforts of having parents and a real family. They are also outside the socio-economic level that is considered respectable. Because they are outside the borders of what is considered socially acceptable, Ponyboy, his brothers, and his friends are labeled "greasers," a pejorative term.
Ponyboy cannot help feeling that life has been unfair to his brothers and him. After all, they have lost their parents. As a consequence, Soda has dropped out of school to work at a gas station. Ponyboy's older brother Darry has assumed the responsibility of acting as a surrogate father to Ponyboy; Darry also works two jobs to try to support his brothers. Unfortunately, their lack of financial security and their social class are the causes of several conflicts.
One of the greatest of these conflicts is the social conflict between the Greasers and the Socs, the upper-class boys. The Socs had previously beaten Ponyboy's friend Johnny Cade so severely that Johnny now carries a switchblade. But Johnny seems destined for misfortune. In Chapter 3, Johnny tells Pony that he will not commit suicide, but he is very frustrated.
But I gotta do something. It seems like there's gotta be someplace without greasers or Socs, with just people. Plain, ordinary people.
Sadly, the only place he finds a short respite from the gang conflict is in the church where he and Pony hide and where, ironically, he is later severely injured.