A very short book that I found myself wishing was a little longer when I found myself confused. But it cleared up for me and I learned a lot about the Angevins. Gillingham sees the Empire as "a family firm"--not united administratively or legally, but rather through personality. The king moved around quite frequently and made his presence known. Administrators were shifted around from place to place.
“The Angevin Empire was a family firm. It existed for the benefit of the family. The interests of the family counted for more than any notion of keeping the empire intact under a single ruler. Even though there are signs of a movement towards legal and administrative uniformity, this was the result of drift, of ad hoc responses to particular problems, rather than of consciously centralising intention.” 116
There was no "Angevin" culture or art. No common cultural ground between regions.
Gillingham thinks that the loss of Angevin territory was inevitable eventually, even had John not lost it himself. As he writes:
“The legal relationship between a king of France and a king of England who held territories on the Continent meant that it was relatively easy for the king of France to legitimize his own actions as part of a legal process. In this sense, legally speaking, the king of France always had the upper hand and it was bound to be the case that, one day, an able and aggressive king of France would find himself opposed by an inadequate opponent…In the event it proved to be fatal when one of the ablest and most ruthless kings ever to rule France happened to be opposed by one of the worst kings ever to rule England.” 125