Grayling wrote a book on the allied strategic air offensive in World War II, "Among the Dead Cities: The History and Moral Legacy of the WWII Bombing of Civilians in Germany and Japan" (2006), as a contribution to the debate on the ethics of war. In September 2010, Grayling was one of 55 public figures who sent a letter to "The Guardian" expressing their opposition to Pope Benedict XVI's state visit to the UK. In August 2014, Grayling was one of 200 public figures who were signatories to a letter to "The Guardian" opposing Scottish independence in the run-up to September's referendum on that issue.