If you've ever owned an iPhone, iPad or Mac, you may have noticed these words printed on the back: "Designed by Apple in California. Assembled in China." But there’s a bigger story behind that simple tagline. Financial Times journalist Patrick McGee tells Piya Chattopadhyay that few understand just how key China and Apple have been to each other's rise. His new book Apple in China explores a relationship that's central to the world as we know it, one which is facing new challenges from tariffs to tensions with Taiwan.