What is the fine-grained topic of the following text: One of the most famous Marines and two time Medal of Honor recipient, Gen. Smedley Butler, wrote a book entitle “War is a Racket” describing how he was a “gangster for capitalism” and U.S. corporate interests. Only return the topic.
Gen. Smedley Butler's book "War is a Racket" and his views on U.S. capitalism and corporate interests.