In one of the most widely scrutinized CEO successions ever, Microsoft directors selected insider Satya Nadella to run the company, only their third CEO pick in the firm’s nearly 40-year history.  His challenges will be enormous. For starters, he will be running a $75 billion+ enterprise with some 100,000 employees, an army of software engineers and many moving parts. For finishers, he will have to change its treads—redirect its strategy—while barreling down a highway with no map for what lies ahead.