A Clash of Kings by George R. R. Martin

A Clash of Kings is the second of seven planned novels in A Song of Ice and Fire, an epic fantasy series by American author George R. R. Martin. It was first published on 16 November 1998 in the United Kingdom, although the first United States edition did not follow until March 1999. Like its predecessor, A Game of Thrones, it won both the Locus Award (in 1999) for Best Novel and was nominated for the Nebula Award (also in 1999) for best novel.
The second book in the "A Song of Ice and Fire" trilogy. Sansa Stark is trapped in marriage to the feeble Lannister boy, child of incest, who is King Joffrey. In the North the Starks prepare for battle with the Lannisters.
A Clash of Kings picks up where A Game of Thrones ended. The Seven Kingdoms of Westeros are plagued by civil war, while the Night's Watch mounts a reconnaissance force north of the Wall to investigate the mysterious people, known as wildlings, who live there. Meanwhile, in the distant east, Daenerys Targaryen continues her quest to return to and conquer the Seven Kingdoms. All signs are foreshadowing the terrible disaster that is to come.
The civil war to claim the Iron Throne becomes more complex. Three kings had declared their claims in A Game of Thrones: Joffrey Baratheon, Renly Baratheon, and Robb Stark. Balon Greyjoy declares himself king of the Iron Islands, launching a massive assault along the west coast of the North, and becoming the fourth of the war's kings. (Summary by Wikipedia)