T. C. Boyle 
The Tortilla Curtain [EPUB ebook] 

When Delaney Mossbacher knocks down a Mexican pedestrian, he neither reports the accident nor takes his victim to hospital. Instead the man accepts $20 and limps back to poverty and his pregnant 17-year-old wife, leaving Delaney to return to his privileged life in California. But these two men are fated against each other, as Delaney attempts to clear the land of the illegal immigrants who he thinks are turning his state park into a ghetto, and a boiling pot of racism and prejudice threatens to spill over.