A Song of Ice and Fire is a series of books that will, as it looks like right now, consist of seven or so books. So far, the first four books have been written and published, with the fifth planned for release later this year. The series is written by George R.R. Martin, an American author of sorts.
A Song of Ice and Fire tells the story of an entire world, in specific the continent of Westeros, and in a lesser sense the eastern continent I dunno the exact name of. Westeros is divided into seven 'kingdoms', governed by a single king at the start of the series. There are many houses on the land, each with their own castle, lands, etcetera. The series tells the story of the land, the houses, the kingdom, etcetera. It does so by sorta telling the story by one character's viewpoint in each chapter.
That's pretty much the structure. In other news, it is the best fantasy series of this moment, beating most books in terms of character development and such. I mean, there are probably hundreds of characters that are described in total, some only by name, others get their own chapters.
The genre is still in the fantasy genre, but only in the details - there are no evil orcs versus the good and hot elves, no teenager flinging stones with magic, etcetera. There's just a few dragons that don't do much yet 'cause they're tiny and it takes years for those to grow up, and only a bit of magic that is used sporadically. The story concentrates more on the people and their stories, the people in the continent, stuff like that.
It's a mature book, stuff like incest, rape, pedophilia, hard violence and stuff like that isn't shunned by the author. Which is good, btw.
Now, I could go and tell a bit about the story itself, but I'll refrain myself from doing so. Also check out the wikipedia page on the book at
http://en.wikipedia.org/wiki/A_song_of_ice_and_fire.
Summary of what I just said: A Song of Ice and Fire is a series everyone, whether you like fantasy or not, should read. Peri0d.