The author of ''Every Mountain Made Low'' and "The Boy, the Bomb, and the Witch Who Returned" is the same person per <a href='http://www.thegearheart.com/'>author's website</a>. The cover artist being the same person is established via <a href='http://www.pjballantine.com/2014/02/06/cover-reveal-weather-child'>Philippa Ballantine's website</a>.