As of April 2015, it was reported to have sold over 60 million copies worldwide.
A Song of Ice and Fire is a series of epic fantasy novels by the American novelist and screenwriter George R. R. Martin. The first volume of the series, A Game of Thrones, was begun in 1991 and first published in 1996. The series has grown from a planned trilogy to seven volumes, the fifth and most recent of which, A Dance with Dragons, took Martin five years to write before its publication in 2011. The sixth novel, The Winds of Winter, is still being written.
The story of A Song of Ice and Fire takes place on the fictional continents Westeros and Essos. The point of view of each chapter in the story is a limited perspective of a range of characters growing from nine, in the first novel, to thirty-one by the fifth. Three main stories interweave: a dynastic war among several families for control of Westeros; the rising threat of the supernatural Othersbeyond Westeros’ northern border; and the ambition of Daenerys Targaryen, the deposed king’s exiled daughter, to assume the Iron Throne. – more on wikipedia (http://en.wikipedia.org/wiki/A_Song_of_Ice_and_Fire)