George R.R. Martin (known as GRRM to many fans) is the author of the Fire and Ice fantasy series, which is what HBO’s Game of Thrones television series is based on.
A Game of Thrones is the first book in the series and was originally published in 1996. An immediate hit and winner of various awards, it was followed by A Clash of Kings (1998), A Storm of Swords (2000), and A Feast for Crows (2005).
The next book in the series is A Dance with Dragons, scheduled to be released in July 2011. The series has been somewhat of a victim of its own success, as rabid fans have grown increasingly impatient with the growing span between each new book, with six years passing since the release of the fourth and fifth books.
Martin has stated that the series will consist of seven books in total, although that should be taken with a grain of salt; A Feast for Crows and A Dance with Dragons are by far the longest books in the series, with Martin expanding the scope and detail of the narrative with each successive book in the series.
The world of Game of Thrones primarily takes place in Westeros, with the primary narrative being the struggle for power between various families and dynasties for control.
Unlike Lord of the Rings and other fantasy series, nearly all the characters are human, although some possess and/or acquire superhuman traits as the series progresses; there are dragons as well as a zombie-like humans known as Others that live in the cold wastelands beyond the Wall (which marks the northern border of Westeros).
Much of the popularity of both the books and the HBO television series is that the fantasy elements don’t overwhelm what at heart is a Machiavellian power struggle played for life or death (usually death) stakes; think Sopranos but with swords and horses instead of Glocks and Cadillac Escalades.