Which figure of speech is used in this text?
Although the author Norman Mailer is no longer with us, his writings live on. His Pulitzer Prize-winning book, The Executioner's Song, remains a classic example of his unique style of writing.

 - euphemism
 - hyperbole
The text uses a euphemism, a polite or indirect expression that is used to de-emphasize an unpleasant topic.
No longer with us is an indirect and more polite way of saying dead.