In 2008, Nokia owned over half of the global smartphone market. Four years later, the company had lost more than 90 percent of its market value and was rumored to be on the brink of bankruptcy. That's when Risto Siilasmaa took the helm as chairman. He's now out with a new book titled "Transforming Nokia: The Power of Paranoid Optimism To Lead Through Colossal Change." He joined Cheddar to discuss.