Hollywood Speaks Out: Pictures that Dared to Protest Real World Issues by Robert L. Hilliard 

Book Abstract (Amazon):

Hollywood Speaks Out explores that rare Hollywood feature that dared to tackle red-hot, social issues whilst American society was gripped by the convulsion and controversy they generated.

• Explores why Hollywood has always been risk-adverse, and how most feature films deal with controversial issues long after the controversy is past
• Organized around such important issues as poverty, racism, sexism, war, anti-Semitism, and homophobia
• Discusses the relevance and the impact of feature films from Modern Times to WALL-E 

Book review via Historical Journal of Film, Radio and Television