Microsoft’s Quiet Office Evolution Under Satya Nadella Mr. Nadella, 48 years old, is more likely to quote German philosopher Friedrich Nietzsche than to scream and shout like his predecessors. His mission is markedly different, too: attempting to make Microsoft more innovative, a change that critics say was long overdue at a company that tended to fall behind in emerging technology areas. Messrs. Gates and Ballmer built a $350 billion software empire on the popularity of Windows, the personal-computer operating system that for years was the default interface of office life. Yet the primacy of Microsoft’s Office software—with its built-in Outlook email, Word for writing documents, and Excel spreadsheets—is no longer a sure thing. Rival tools for office tasks have arrived, include file-sharing service Dropbox Inc., Apple Inc.’s iPhones, and workplace versions of Google Inc.’s Gmail and Docs, many of them free. Thus Mr. Nadella is intent on talking about the evo...