Lioness Rampant by Tamora Pierce
Series: The Song of the Lioness #4
The final book, I think this one has the richest description, the best characters. It is a perfect culmination of all of the wondrous things in the previous books. Enemies of all types reappear, loved ones are lost. The circle of “boys” that you so loved from the beginning are now a woman, men and a king. The danger is taken to the next level. One thing I find so amazing about these books is that the reader grows with Alanna. No matter what your age, you grow a little every time. And then of course this amazing world draws you into the next series where you see some old friends in a new light and meet all sorts of new friends.
(This is the fourth book of The Song of the Lioness quartet, a Tortall series.)