The Oathbound (Vows & Honor #1)
The Oathbound is the first in a trilogy set in Mercedes Lackey’s wide-sweeping world of Valdemar, and if you’re new to the world this is as good a place to start as any. You’ll learn a lot about the world, though it takes quite some time until you actually meet any Heralds of Valdemar, and they are the main focus of many of not most of the books set in this world. And the series has been around long enough that I’d be surprised if any longtime fans of fantasy novels hadn’t at least heard of it.
This particular book focuses on a paid of blood sisters at a point after they have found their common purpose, blood-bonded to each other, and now find themselves at a bit of a loss of what to do next since their main purpose in life seems to have been completed. Now, this may seem like it’s starting part-way through the story. In a way, it is. Tarma and Kethry met (and accomplished that main purpose) in a short story which was published in the anthology “Sword and Sorceress III”. However, you can easily pick up this book without having read the prior story and not get lost.
Originally published in 1988, this book has stood the test of time pretty well. I’ve read it multiple times, and it (like the rest of this trilogy) remains on my keeper shelf. That’s not something that all of the Valdemar novels can say. I actually like the older ones better than the newer ones, in general.