Original: The controversial Goosebumps series was often challenged in American libraries for their sometimes-violent content; the novels were fifteenth on the American Library Association's list of most frequently challenged books from 1990 to 1999.
Simplified: The Goosebumps series sometimes contained too much violence, so some American libraries disagreed with having the books there; the novels were fifteenth on the American Library Association's list of most frequently challenged books from 1990 to 1999.