The cover mentions "1: Steel and Snow", so I thought it was the first part of a new set of books.
It turns out that 'A Storm of Swords' is the third installment in the series of 'A Song of Ice and Fire', which is the series that starts out with 'A Game of Thrones'. And the British have spliced the third part into two books (at least for the paperback edition), which is what I've acquired.
Gah, I need to go out shopping for books again. :(