I rarely think the first book in any series is a must read. It usually takes me two books to decide if a series will be any good or not. That being said, I thought Duty to the Dead was a very well written first book. Bess does a few slightly unbelievable things but wasn't enough to make me dislike her.

I really didn't like it, but we may have different tastes in such books. I mostly had trouble with the historical setting, I think.