D. is our leading scholar of Xenophon's Socratic works, and this valuable volume, together with his magisterial edition of the Memorabilia (with M. Bandini, published in 2000 [vol. I] and 2011 [vols. II and III]), will provide an essential foundation for all subsequent work on Xenophon's Socrates.

The volume consists of nineteen essays, including an introductory overview and a helpful set of indexes. All but one of the essays have been published before, but they have been revised for this volume, and their republication here makes them far more accessible than they were in their disparate original locations. The central essays are those on the relationship between self-control, self-sufficiency and wisdom for Xenophon's Socrates, but D. also addresses Socratic politics, friendship, economics (oikonomia) and religion (especially the divine sign). D. also provides helpful guidance to the reception of Xenophon's Socrates through essays on the Socratic question, Schleiermacher, the Straussian reading of Xenophon and Montaigne. A pair of essays on Plato close the volume, helping D. to draw a contrast with Xenophon. As befits the editor of the Memorabilia, that work is usually central here, but we do find important commentary on the Oeconomicus and Symposium as well. Perhaps the one topic noteworthy by its relative absence is the trial of Socrates; D. is much more interested in the views of Xenophon's Socrates than in Xenophon's defence of Socrates, or the historical trial of Socrates.

Three major theses characterise D.'s approach. The first is that the search for the historical Socrates is vain, given the fictional nature of Socratic literature. The second thesis, which dominates many essays in the volume, is that there are fundamental and irreconcilable differences between Xenophon's Socrates and Plato's; this point reinforces the first thesis, as it is precisely the differences between Xenophon and Plato which make recovery of the historical Socrates so difficult. A final argument is that once we cease to approach Xenophon hoping to discover the historical Socrates, or even just expecting to meet the same character we know from early Plato, we can recognise the coherence and value of Xenophon's own account.

D.'s introductory chapter (a revised version of his 2006 English language introduction to Xenophon's Socrates in the Blackwell Companion to Socrates), lists some 21 differences between Xenophon's Socrates and Plato's, many of which resurface in later essays. Some of these differences are doctrinal: for example, Xenophon's Socrates appears to endorse harming enemies, while Plato's Socrates does not. But more often the differences are about how Socrates operates, how he characterises his activity and how it appears to others. Xenophon's Socrates is more dogmatic than ironic; is not ignorant but knows how to define the virtues; does not often practise the elenchus; professes to teach (though he never quite claims to teach virtue); and is generally speaking less strange, and less likely to be at a loss or to confuse others. Some of the differences are outright contradictions, but more are distinctions in emphasis or presentation. And there is, of course, plenty of room for debate about just what is meant by ‘Plato's Socrates’. D. sometimes treats the whole of the Republic as Socratic, whereas elsewhere he more conventionally limits Plato's Socratic phase to earlier works.

Though D. does not quite characterise it this way, we may summarise many of the differences between Plato and Xenophon by noting that Xenophon's Socrates is, above all things, helpful; this is the overarching thesis of the Memorabilia (1.3.1). To show just how helpful Socrates was, Xenophon confronts him with a varied group of people in need of different sorts of advice, which his Socrates freely and confidently dispenses. But choosing to demonstrate how helpful Socrates was need not entail denying that he engaged in the sorts of things we are familiar with from Plato. For Xenophon does allude to Socrates' habitual search for definitions (Mem. 1.1.16) and to his use of the elenchus (Mem. 1.4.1); he does not deny that Socrates did such things, and he sometimes, if rarely, shows Socrates pursuing definitions of ethical terms (Oec. 1) and practising the elenchus (Mem. 4.2). His point seems to be not that Plato's portrait was wrong, but that it was incomplete. Of course, Xenophon may be wrong about this: perhaps he failed to recognise how radically his Socrates differed from Plato's.

For D., the most fundamental difference between Xenophon's Socrates and Plato's lies in Xenophon making self-control (enkrateia) the key to Socrates' teaching, where wisdom (sophia) is the central concern of Plato's Socrates. As D. frequently reminds us, Xenophon's Socrates makes enkrateia the foundation of virtue (Mem. 1.5.4) and devotes long sections of the Memorabilia to enkrateia (1.3.5–14; 1.5; 2.1; 4.5). Plato, while portraying Socrates as self-controlled, never even mentions the term before the Gorgias; for the intellectualist Socrates of early Plato, wisdom suffices, and self-control is of little concern. D. shows how these central differences play out across a wide range of topics; Xenophon's Socrates is consistently more interested in the body, in material things, in economics, in the practical aspects of political life. Enkrateia enables Xenophon's Socrates to reach a sort of self-sufficiency (autarkeia) that Plato's Socrates never lays claim to; where Plato's Socrates is always a very human striver after wisdom, Xenophon's Socrates, thanks to his superlative self-control, attains a god-like state of self-sufficiency.

We should, however, be careful about saying just how enkrateia replaces sophia for Xenophon. Enkrateia certainly replaces sophia as the dominant theme in Xenophon's depiction of Socrates, but this does not mean Xenophon gives enkrateia the same role in Socrates' thought that sophia has for the thought of Plato's Socrates. Xenophon's Socrates says that enkrateia is the foundation of virtue, but never says it is a virtue. And his Socrates can say things that are as intellectualist as one could desire (Mem. 3.9.4). The key task here is to understand what ‘intellectualism’ means for Xenophon and Plato; recent trends in scholarship on Plato's Socrates (as in Brickhouse and Smith's 2010 Socratic Moral Psychology) would leave room for the sorts of non-rational desires that make enkrateia valuable. This would remove much of the doctrinal divide between Xenophon and Plato here. Xenophon's Socrates certainly makes more of his ability to do without help from others – at his trial, for example, he, unlike Plato's Socrates, never even suggests a counter-penalty that he might need help to pay. But Plato's Socrates also sometimes displays a godlike ability to endure cold, do without sleep and resist the effects of alcohol. It is just that he does not deign to talk about such things. Xenophon demystifies these aspects of Socrates.

D. argues that if we separate Xenophon from Plato and the elusive historical Socrates, we will be freed to study Xenophon on his own merits. Comparative study with Plato may not teach us anything about the historical Socrates, but it will help us better understand the distinctive characteristics of our two rival portraits. I would emphasise overlaps as well as differences, bring Xenophon on board as an informed reader of Plato (whose readings should influence ours), and suggest that we study not only rival accounts of Socrates but the intertextual figure who spans our sources – presumably because our sources reflect the historical Socrates. In short, one can differ about just how ‘other’ Xenophon's Socrates is. But no one would deny that there are substantial differences between Plato and Xenophon, and D.'s signal achievement is to demonstrate that these differences are not errors or simplifications on Xenophon's part, but integral features of Xenophon's consistent, substantive and valuable portrait of Socrates.