Power lists are always fun, argument-provoking and subjective, for all of which reasons ArtReview’s Power 100 makes for great reading. Begun in 2002, it maps the highs and lows of the global world of art. While some collectors (such as French billionaire Francois Pinault, No. 1 in 2006 and 2007) or usually gallerists (Larry Gagosian, No. 1 in 2004 and again in 2010), have been constants on the list, others such as powerbroker collector Charles Saatchi (No. 1 in 2002) have fallen completely off it. This year’s No. 1, David Zwirner of the eponymous Zwirner galleries, made his debut in