This relatively short Crichton book is unique and engaging. Chrichton sets up the book to be an ancient travelogue manuscript in the year 922 A.D. from an arab courier of the caliph of Baghdad. As inspiration, Chrichton used both the story of Beowulf and Ahmad Ibn Fadlans personal account of his actual journey north and his experiences with and observations of Vikings.
As a muslim, Ibn is appalled by filthy and barbaric vikings who conscript him into their journey northward to battle the 'eaters of the dead' - a terror that plagues the men of the north, a near-human (Neanderthal men by Chrichtons account) army of creatures that invade each evening when under the cover of darkness and mist. For several weeks, and several battles and adventures, Ibn is transformed into a warrior like his viking counterparts.
While not Crichton's best work, the books unique perspective and short length make this a worthwhile summer read by the pool or beach.