If there's one man whose opinion matters more than any other on global energy markets, it's Daniel Yergin. Yergin is the chairman of IHS Cambridge Energy Research Associates, a major energy consultancy, but he's best known as the author of a magisterial history of the oil industry called The Prize, which won the 1992 Pulitzer Prize for non-fiction. In 2011 Yergin came out with his long-awaited follow-up, The Quest, which surveyed the recent history of the energy industry, from oil to nuclear to renewable power. If it didn't quite have the compulsive readability of The Prize — they just don't make obsessed oil tycoons like they used to — The Quest captured the energy industry in transition, as renewables soared, nuclear fell and unconventional sources of fossil fuels like shale gas threatened to change the whole game. Yergin hasn't always been perfect as a predictor — he's been accused of ignoring the risks of peak oil — but his is a voice that's always worth heeding.