Complex sentence: In 1954 John Castle published a book, "The Password is Courage", describing Coward's wartime activities; this was adapted into a 1962 film of the same name starring Dirk Bogarde.
Split into simpler sentences: In 1954 John Castle's book, "The Password is Courage", describing Coward's wartime activities, was published. This was adapted into a 1962 film of the same name starring Dirk Bogarde.