(No spoilers here!)
Finlay does a whole lot of things right in this book (setting it far, far above Katherine Kurtz's disappointing 1996 Two Crowns for America, the only other work I've run into that handles witches and the American Revolution). His characters are human, believable, and sympathetic. They know weakness and uncertainty; they make mistakes; they change their minds. For the most part the emotional interactions between these characters are handled with a subtle, even lovely, touch. Finlay conveys big, important, tragic things without melodrama, both at the personal level and at the "Shot Heard Round the World" level. Which is not to say this book is the literary equivalent of a chick flick; on the contrary, the battles--again, both large-scale and small--are visceral and gripping, and they read fast. Even the reader familiar with the historical encounters can suspend that knowledge of the outcome and worry over how things will turn out.
In fact, the integration of history with fiction is something Finlay always does well. (His 2002 novelet "We Come Not to Praise Washington" was a finalist for the Sidewise Award for alternate history). Finlay is a trained historian who's done plenty of academic work on this era, but don't let that scare you off, because he's a storyteller first. None of this reads as dry history; in fact this novel manages to breathe real life into an era that everyone knows at least something about, reminding us that the patriots and tories of the American Revolution had real-life, tough decisions to make, balancing love and family and fear against any political considerations. People died, many of them senselessly. Others were displaced or went hungry. Where pop history forgets them and academic history might render them dry figures, Finlay's characters fear and feel these losses. Maintaining historical gender roles while writing strong female characters is another place Finlay excels. The prose and dialogue convey the period and lifestyle well while remaining seamlessly readable, resorting neither to modern slang nor stilted historical usage. (Yes, as another reviewer noted--there's a stretch of thees and thous. But this comes from someone who would indeed have spoken like that, doesn't actually happen often or last long, and even gets noticed and discussed by the main characters later.) History geeks will enjoy having a few fun tidbits thrown their way, such as the answer to the historical mystery of the shot that started it all; similarly, the dialogue near the end over the name of a hill where a battle was fought manages to be both funny and sadly profound.
All of the above said, while this is an excellent book, it is not a perfect book. For instance, a long stretch of the story relies upon the POV character not communicating information he has to the characters around him; I didn't buy his reason for this, in large part because he never quite explains it. Perhaps his reason was valid, but I wanted him to at least acknowledge (to the reader inside his head) that he's withholding info and why, especially as the people around him discuss wishing they knew that piece of information. But about the time I was starting to worry that it would annoy me if the whole book relied upon what felt like a contrived lack of communication, all was revealed. From then out, the characters' logic and knowledge, or lack thereof, made sense, making this one, fairly early incident one of the few things that bothered me.
All in all, this book is a great read. I look forward to the next book in the trilogy, A Spell for the Revolution (and yay, it's due out next month, so we don't even have to wait very long!)