The names "Ralph," "Jack," and "Simon": R.M. Ballantyne: The Coral Island.
The Coral Island was a classic 1857 "Europe can better the world through conquering it and forcing Christianity upon everyone" book. Golding read it when he was a wee boy, considered it racist, and fashioned Lord of the Flies as a response to Ballantyne. While the boys in The Coral Island encounter evil "primitives" (read: natives) and find a happy ending by burning "the false Gods" of the inhabitants, the white boys in Lord of the Flies realize that they're evil themselves. Golding argues that darkness is internal and inherent, not something you can attribute solely to those with a different skin color than you.