Writing about spies, one does wander into military matters, rather as cooks lead us to eggs and Olympic swimmers leave their trail of chlorine and damp towels.
I didn't study battles and weapons and armies on the march, per se, because I'm not wildly interested in that sort of thing.
My spies, though, are.
So I had to know something or sound like a fool.
Fortunately, there's any amount of primary source material on life in Napoleonic armies. Memoirs. Diaries. Harry Smith, for one. And there are pictures. Give me a picture of soldiers eating dinner around the fire over any number of battlefield maps and tactics.
Mostly though -- when I needed a military or weapons detail, I'd go looking for that specific bit. There's many downloads of antique guns in the innards of my computer.
As to the medical details ...
Anneka at work on the bullet arose from a desire to have her do important, useful, heroic and at the same time at least vaguely plausible things. Taking out a bullet falls into this category.
Let me just mention the balance of power in the book, because it's something I gave a LOT of thought to, in writing.
At this point in the story, we have her in a position where she should be entirely powerless.
I'm trying to show that her real power -- her ability to affect events -- continues strong as ever.
That day, Grey shows his power by keeping her from running away.
She shows hers by chosing to save a man's life.
Who has the real power that day?
As to the operation itself, I have a Masters in mammalian physiology. I've done a fair amount of small animal surgery, so I come to that scene with a 'feel' for how this would work. And I ran the final draft of the scene under the eye of a physician who hangs out at Compuserve Books and Writers who's kind enough to advise writers on medical things.