The fifth book, A Dance with Dragons, had released in 2011 and since then fans have been patiently waiting for the next installment. The author has been taking an exceptionally long time to complete the sixth book in the series, and fans are running out of patience. Even the Game of Thrones series is catching up with the book, with the fifth season coming out shortly.
The Game of Thrones show-runners, David Benioff, and Dan Weiss has made it very clear that they will not continue after season seven, and Martin is under pressure to complete the book and series quickly. He feels that once the HBO series is done, the sale of books will go down, since the ending will already be depicted there.
Martin reportedly said at a Game of Thrones press event that he is giving the finishing touches to the novel and will declare the official release date once he has completed the sixth book. This has made fans hopeful that the sixth book might be released with A Knight of Seven Kingdoms, in October this year.
Until The Winds of Winter is out, fans can keep themselves occupied with the Game of Thrones Season 5 that returns on 12th April.