From all the hype I've heard about this book (and movie), I knew it must be a good read. And it is.
The Other Boleyn Girl is told from Mary Boleyn's point of view, the sister of Anne Boleyn who becomes Henry VIII's second wife. As a historical fiction piece, I found it very interesting and well written. Gregory certainly seems to have the historical details down, as my research proves (i.e. Wikipedia) and that is important for a story such as this. I'm not sure how much Gregory embellished, though I did hear an argument that she didn't play very close attention to some characterizations of people.
Either way, the characters are very engaging and interesting, the pacing is well managed (except it does drag a little towards the end. Maybe it's just because I was antsy for the beheadings...), and it's a very accessible read.