On one hand, the book is written as a novel. The characters are very well designed, Especially knowing that, aside from a couple of the important historical figures, not much is known about most of the individuals. The dialogues feel natural and allow for a fluent story. Regarding the person of Vlad Tepes, in my eyes at least, the design is perfect, and I feel great satisfaction in his words and actions - the way I would like to think Dracula to have been like.
On the other hand, the book serves well as an account of historical events. The author himself states did all historical information is confirmed by (at least) two sources. Armies, fortifications, weapons, armor, towns, clothing, the landscape - everything is Depicted in a vivid and picturesque way. One is drawn into the emotions, into the heat of battle, without loosing the overview.
You will surely be tempted to read the book in a single breath, and through all the turmoil, the book delivers a most satisfying end. Even if you are new to this topic, you will have a great time, and for the true fans among you, the title is bound to meet your expectations.
