When Boris Yeltsin appointed Vladimir Putin prime minister in 1999, the question everyone asked was, "Who is Putin?" Remarkably, in 2015, there are those who are still asking the same question. He remains a divisive figure, inside his country and outside, with vociferous critics and equally ardent supporters. Putin's rule has often seemed deliberately inscrutable, but the key to understanding one of the most consequential leaders in the world today lies in his family history, his upbringing, and his rise to absolute power in Russia.