This is a relatively short but scholarly book (some 200 pages of main text) which focuses on the relations between the Sassanian and Roman Empires and their respective Arab allies, the Nasrids (better known as the "pro-Sassanid" Lakhmids) and the Jafnids (often called the Ghassanids, and generally "pro-Roman").
The author prefers using the dynastic rather than the tribal terms because, as he shows throughout the book, the following of the two families are more than likely to have gone well beyond a single tribe or clan.
This book is very much worth reading for anyone wanting to learn about the rather complex role played of the Arab clients/allies of the two Empires. It is also of interest to understand how Arabic pre-Islamic identities were starting to emerge and be built during the sixth century AD.
One of the most fascinating elements contained in this book is that it shows the evolution whereby groups coalesced into loose confederations around charismatic leaders and their descendants. The power of these leaders and their families was largely derived from the support - recognition, titles and subsidies, in particular - which they received from the respective Empires. The author is careful to show that they never quite evolved into fully-fledged vassal states, although their leaders became more assertive and more ambitious towards the end of the century. Greg Fisher also shows how, to build up their power while not losing touch with their followers and becoming alienated, these leaders had to play a careful balancing act. He also describes how ultimately vulnerable they were and how, by the end of the century, both Empire moved in against them, squeezed them and suppressed them, because their respective "clients" were becoming incontrollable and a bit too assertive.
The book mainly concentrates on the Jafnids and Ghassanids, simply because the sources, both written and archaeological, are better than for the Jafnids (Al-Hira, their capital, which is nowadays in Irak, has never been properly excavated, for instance). There is however considerably more to the book than that, for it also contains interesting insights and discussions on early pre-Islamic written Arabic and the progressive building of an Arab identity, together with what little we know about the other confederations in the Arabic peninsula.
The study is also worthwhile for its balanced discussions on Arab Christianisation and, more generally, on the evolution of religious beliefs in the Arabic peninsula before the birth of Islam. It also puts pay to the sometimes simplistic dichotomy that can be drawn between sedentary and nomad populations, which could, at times, belong to the same tribes.
Finally, perhaps the main merit of this study is its attempt to "set the record straight" by attempting to keep to what little we really know, instead of speculating as some authors have been tempted to do, and by avoiding to "overplay" the importance of these client Arabs. As the author states in his conclusion, "although they are deeply relevant to the study of Late Antiquity"... they never were of central importance for the political and military concerns of their patrons, as some suggest" (Irfan Shahid, in particular). Nevertheless, "they are extremely relevant to the study of state-tribe, centre-periphery and empire-client relationships", as the author has shown so well in this book.
Four solid stars.