Eva Holland survived her worst fear. Since childhood, she worried about losing her mother. But in 2015, after her mother died and she endured the grief that followed, she also found new strength and hope—and decided to write a book about why fear takes such a hold of just about everyone. Holland interviewed scientists seeking solutions, considered an interesting form of therapy, talked with people who have a rare immunity to fear and kept challenging those terrors that still try to haunt her. “Hopefully I make a useful guide,” she told the New York Times. “Or a crash test dummy.”