These are European `Dark Age' army lists for the Fields of Glory rules. 24 different armies are covered (including the Bretons and Lombards who are only covered as allied contingents). These armies cover much of Europe from Spain to Russia, but with perhaps particular attention paid to the UK. Most armies are covered by a short historical overview, sometimes some notes on particular troop types within the army, then lists for the armies and allied contingents. Some of the lists have variants and restrictions depending on the year. I'm in no position to judge the historical accuracy of the lists but there was nothing that seemed too implausible or surprising.
The illustrations are taken from books from the Osprey series and are generally quite good, and are supplemented by pictures of appropriate painted 28mm figures. The format is generally easy on the eye. The army lists are done in tabular format which might look a little complicated but is very easy to grasp. Some of the armies have a suggested starter army as well which is a good idea for the beginner. In substance, they are similar to those used in the WRG DBM Army lists changed appropriately to use with the Fields of Glory rules. I don't use these rules myself, but they can be used to give appropriate armies for other games. However, although the book has much higher production values, it doesn't contain as much information as the equivalent DBM lists.