I received a copy of this book as a GoodReads giveway.

I picked up the first book in this series (The Blackthorn Key) at the house where I was staying on vacation last summer. I love historical fiction, and was looking for a nice light vacation read. It delivered in spades - I finished it in two days and quickly tracked down the next book (Mark of the Plague). I really love the characters: the apprentice Christopher, who rises from an impoverished life due to a combination of his own intellectual gifts and the love of a kind adult; Tom, who is a good and loyal kid despite having a dad who's a jerk; and Sally, another orphan whose smarts and loyalty make you root for her. This book takes the trio to France, where they must infiltrate Louis XIV's court to stop a plot to assassinate the Royal Family.

Obviously a book written for young adults probably simplifies history a fair bit, but this is mostly lightly done, and I'm willing to overlook the implausibility of a member of the merchant class being able to successfully pose as a nobleman in a court as famous as France's for its intricate protocols, because the plot is so much fun, the characters are so likable, and the historical research on a lot of matters is so good. Sands has clearly done his research on remedies and poisons, and on ancient codes and ciphers.

The ending makes it clear that this series is more than a trilogy, and I'm looking forward to the next installment.