Georgette Heyer was the master of historical fiction, particularly in the Regency era. An Infamous Army focuses more on historical events versus romance than most of her other novels, its central theme being the description of the Battle of Waterloo and the events leading up to it.

The main characters in this story are Colonel Charles Audley and Lady Barbara Childe. Charles Audley appeared as the younger brother of Lord Worth in Regency Buck, and Barbara Childe is the grandaughter of Dominic and Mary from Devil's Cub. There has been a slight fudging of historical dates to fit these characters in, but it is interesting to read more of Lord Worth and Judith's marriage in this story as parts of the book are told from Judith's point of view. Many readers may find Barbara Childe a somewhat unsympathetic character; her wild behavior and often cavalier treatment of Charles Audley can be hard to stomach. However, as the book continues and the battle takes place, she shows more depth to her character despite her faults. Charles's instant attraction to her isn't always understandable, but in some ways the love story in this book feels very much a hook upon which to pin the main thrust of the book: the battle itself.

The romance in the story is definitely subsidiary to the historical events, which are described with an excellent attention to detail. The way that society in Brussels continued its usual round of balls and soirées as the French troops drew nearer is fascinating, as are the portrayals of several historical characters (not least the Duke of Wellington), the horror and agony of war, and the real possibility that Napoleon's troops might have prevailed.

Although an excellent book, the heavy emphasis on the fighting of the Battle of Waterloo means that it isn't particularly easy reading. It's also quite a long book, and with the usual Heyer writing style full of cant phrases can be hard to understand for a first-time Heyer reader. Still, she remains many people's favorite historical novelist for good reason. This book does not disappoint with the quality of the writing, the historical detail and the author's excellent storytelling ability.