This being part one of the three part Warlord Chronicles series, but I'll just be writing one review for them all as they are all of equally high quality.
Lets get to the meat of things straight away, this is a story about Arthur. However, there are no knights in shining armour and no towering spires. This is a tale of dark ages Britain as told through the eyes of Derfel, one of Arthur's closest companions. It is the story of the warlord Arthur and his ongoing dream to push back the invading saxons, all the while dealing with treachery from his friends and the schemes of those closest to him.
It is one of those books that redefines how you look at an age old story. No other Arthur story will work for me now as they all look ridiculous. The characterisation is utterly fabulous. Lancelot is utterly despicable (not a spoiler at all), and Merlin is gloriously conniving and twisted.
I cannot recommend these books highly enough. They are historical fiction (and Cornwell is happy to admit when he is taking liberties) but they read almost like fantasy, so different is the world of Dark Ages Britain from our own.
Even if you have no interest in the Arthur legend, try these out. While they could be described as being about the wars Arthur & Derfel fought or the loves and betrayals, I would have to say that the one thing which stands out in this story more than anything else is that it is a tale about friendship.