Professor Emmanuel Roucounas, born in Zagazig, Egypt, now in his 88th year, takes inspiration apparently from that other Greco-Egyptian author, Athenaeus. In Athenaeus's The Deipnosophists, a series of erudite discussions by philosophers and other learned personages occur over dinner. Rather than presenting us with a singular thesis, Roucounas gathers the authors he tells of and adopts something of Athenaeus's dinner conversational tone. In the Preface, he describes the landscape of theoretical writings on international law as one consisting of some 500 authors, whose contributions require an unusual structure and approach to the way we might understand and explain them. When put together, the array of voices resembles what Roucounas terms ‘a choir group without a choir master’. There are voices of ‘widely recognized virtuosi, tenors, sopranos, prima-donnas, basses and sotto voce chanters, imitators, and those who only hum or sing in languages not understood by the others’. There are soloists, ensembles, and even madrigalists who use different melodies. While some exceptions lend a ‘semblance of disarray’, most carry on harmoniously. Some have never even heard of the others, whom they simply ignore, but all are together on the same stage. The distinguished author, a leading light in the firmament of Greek international law scholarship and member of the Institut de Droit International, considers that our choristers comprise some 30 or more subgroups, although only three or four major groupings are usually observable to the naked eye.

Professor Roucounas, calling his book a mere sampling of these various writers’ views, admits his is a daunting task, but says simply that the challenge of ‘seizing the momentum’ to offer a rendition—an ‘image’, as he puts it—of the state of theory at this time has proven attractive. He cautions us, however, that there is mystery involved when one attempts to answer the question—When does a voice become a theory? In the age of the blogosphere and countless publications in endless journals that becomes not only a real question but one bound up with the technological transformation of international law scholarship.

Thankfully, the author confines himself to the more traditional sources of writing. Part I is about the nature and place of theory, and the history of theory. Part II comprises a survey of ‘enduring’ and new schools. It discusses liberal agendas; the ‘positivist stronghold’; natural law writing in all its guises, be it repackaged, explicit, hidden or borrowed; realism; idealism; rationalism; pragmatism; empiricism and formalism. There are others, classified separately, though most of which we might subsume under the broad church of realism—the Yalies, Harvardian crits, fem-crits, bloods and Twailers, the economists, and public choice theorists. There is functionalism, instrumentalism, there are regime theorists, European crits and more, much more. We are treated to a kaleidoscope of colourful cameo appearances.

Professor Roucounas offers terse but gentle opinions on a seemingly endless array of theorists new and old. The views on contemporary authors are especially fascinating, expressed—as with our learned banqueters in the Deipnosophists—as if we had caught the author himself in mid-dinner conversation. Harold Koh did that, here is Stephen Krasner's influence on lawyers, Hermann Mosler thought that of regimes, Keohane understood this, but for Stephen Toope and also, lest I forget, both Jutta Brunée and Stephen Toope did once elaborate upon and emphasise … then, suddenly, we are plunged into Diogenes, Demetrius of Phaleron, whom one is told wrote the first book on international diplomatic law.

I am now at Chapter 12, the tour d'horizon of 32 schools has nearly come to an end and I think that we are at the apex of our imaginary dinner conversation. Roucounas has taken over completely by now, the assembler is assembled. He presents his observations on legal cosmopolitanism and how what positivists think of as the sundry things of monism and dualism have become Durkheim's ‘dual nature’ in individuals, national loyalty vying with our cosmopolitanism. We are soon past the Marxists and now are in the midst of the English School of international relations. Roucounas's message is clear. International law writings come from many different corners and places—there is a ‘plethora of methodological and substantive angles’.

Then to the final part, Part III, the peroratio, where Roucounas discusses how these writings relate, after all, to fundamental questions, to particular themes, and how they also foretell future directions. Roucounas's is a teacher's voice, which speaks modestly of the importance of what others think—‘Pierre-Marie Dupuy writes that the community of nations exists because the law says so’, PS Rao ‘underlines that nearly 150 developing countries, representing 80 per cent of the world's population …’.

There are many of us who stick to the VCLT, the ARSIWA and such, and mind that we know the blurry parts between the two; who are content simply that we know the Monetary Gold principle. Even so, there are moments when forensic preoccupations offer little escape from the broader realities. The world changeth. Today some suggest that the ‘rules-based order’ needs re-assertion, but the reply in turn has been that what matters is only the United Nations rules-based order, no more and certainly no less. With talk of a New Cold War and hybrid warfare having already commenced, international lawyers might once again ask large questions. Theoretical questions, historical questions, and questions too about the history of our legal ideas. What caused natural law thought to cede to positivism and a law of nations? Then brought decline to the ‘gentle civiliser of nations’, or so it is viewed through a particular cultural lens, and brought also an end to idealism at the turn of the previous century? What drove realism to the theoretical foreground in that subsequent Age of American Empire? Did legal realists appear before or because of a Pax Americana? Did Empire call to New Haven for a new kind of scholarship fit for a new age, and call on Henry Steiner for his vision of global values? Just as American businesses abroad called to Vagts, Steiner's colleague in Cambridge, when the European empires had crumbled while American capital spread and spread.

The importance of Professor Roucounas's effort is that his opinions on theory and on the various theories are never far from an accompanying sense of history. It is that combination which makes the present book and turns what might appear to be no more than a meticulous, often too self-effacing, classification exercise into an interesting set of messages. Messages, for example, about how our ‘ontological’ preoccupations concerning the existence of international law gave way to ideas about fairness as the late Thomas Franck saw it.

So, Professor Roucounas's book—which but for its size we might in some senses compare to Lyotard's La condition postmoderne (Bennington and Massumi, translation)—comes at an interesting time. If there is a complaint, it is that we would want to hear more of the author himself. Yet suddenly, startled, we realise our imaginary dinner conversationalist has been there all along reflected in a mirror. Our sense of Roucounas the author unfolds, unhurriedly, as if in an evening spent with an engaging stranger. It is not a small book but for what it is is admirably compressed, and time has flown.

A Landscape of Contemporary Theories of International Law by Emmanuel Roucounas, which includes a separate author index, deserves to be read widely; preferably by those in the first blush of love with the subject while for others there is still the prospect of feeling young again and in love.