This book is not good. I have to agree with the other negative reviews, and say that it both does not cover much information, and that it contains mostly the author's own opinions and biases.
International relations covers many topics, including shipping and trade relations (along with related subjects such as economic sanctions, tariffs, trade deals, embargoes, and blockades), warfare and spycraft, international treaties and organizations for research and defense, the use of internal and external propaganda, foreign aid and ambassadors, puppet and buffer states, currency exchanges and the IMF, international courts, extradition and refugees, historical colonialism, the geographic availability of natural resources, debates over patents, the internet, and outer space, etc. This book covers none of these things, aside from a brief mention of the existence of a few organizations like NATO and the EU.
Then there's the issue with the author's own biases. For example, he repeatedly describes theories, organizations, rulers, and governing styles that he doesn't like as "silly", "so-called", "brutal", "humiliating", "irrational" etc. This kind of language has no place in what is supposed to be an academic piece of work. This is made worse by the fact that his assertions are usually very shallowly analyzed and not supported with evidence. For instance, look at his description of coercive states:
"What are the major features of the coercive state? It is not surprising to find that they are wholly incompatible with the key characteristics of liberal democratic states. Whereas the latter come to power by the consent of the governed, that is through regularly conducted free elections, the typical coercive regime achieves power as a result of a coup, a revolution, or a successful insurgency, often supported only by a small minority of the population, and frequently resorting to terror attacks against civilians as part of its tactics for seizing power. Once in power the typical coercive state almost instinctively employs extreme violence or terror to intimidate and suppress any threat to its power or even on the pretext of threats or dissent which are shown to be imagined rather than real."
First, this is reductive because most modern governments came into being via coups, revolutions, or successful insurgencies, with mixed degrees of community support. Examples include the United States, France, China, Afghanistan, El Salvador, etc. Clearly these countries run through a whole range of governing styles. Furthermore, the author asserts a connection between a state's governing structure and its degree of coerciveness without backing it up. It's well known that democracies can have problems with majority rule leading to violent suppression of economic or racial underclasses, with issues ranging from apartheid and unfair policing to civil war. This has been seen in the United States, South Africa, India, many Middle Eastern countries after the Arab Spring etc. If you're going to be making statements about liberal democracies and coercive states being incompatible, you have to at least try to explain your reasoning. In addition, from further discussion it is clear that the author uses "coercive state" as a purely political term to describe non-democratic states. For example, the author describes the use of military force on a state's own citizens as a feature of coercive states, describing it as "extreme violence or terror", but later in the book defends the use of military force on a liberal democracy's own citizens in instances of putting down "unrest" and "insurgencies". What then is the point of labelling a state as coercive? Not only is this essentially propaganda, but it also doesn't have much to do with international relations. This is just one example of why I feel this book is more opinion-based than fact-based.
(EDIT: I wrote this review a few weeks before the George Floyd protests, and had to come back and double underline this point about coercive states. This further demonstrates that the views expressed in this book are ideologically driven and not based on actual analysis.)
I think a good book on international relations should factually describe what states have done and continue to do, with a lot of examples. For example, I recently read a book on naval tactics that talked about the role of the military in protecting access to trade routes. This book talked about how countries structure water-based shipping routes, and discussed the relationship between a nation's economy and its access to water. It talked about how blockades are enacted, and how nations make defense pacts or perform military posturing in order to protect their own shipping interests. This book had a lot of historical and modern examples of naval use, and I learned a lot about how nations actually interact with each other in this realm. This kind of book is better, I think, because it describes how nations actually cooperate or fight with each other, how they have done so in the past, and why they continue to do so. Wilkinson's book, on the other hand, is very shallow and opinionated. A lot of it reads like "This state is good. This state is bad. The good states need to control the bad states", without really describing any details about how these states interact at all.