When Dionysius I of Syracuse became master of Sicily in 405, he was arguably the first Greek leader to employ an army composed of mercenary troops. If the men who had gained immortal glory at Marathon or Thermopylae were the living embodiment of one ideal and one soul, the spirit of the classical polis, the troops of Dionysius were a military Babel of different languages and styles of combat. As Diodorus puts it, ‘he had gathered his mercenaries from many nations; for he was eager to have every one of his soldiers armed with the weapons of his people, conceiving that by such armour his army would, for this very reason, cause great consternation, and that in battle all of his soldiers would fight to best effect in armour to which they were accustomed’ (Diod. 14.41.4–5). According to B., a well-known expert in the world of Greek mercenaries, the campaigns of Dionysius are a crucial turning point in the history of Greek warfare, signalling the decline of the once-dominant figure of the hoplite (pp. 342–3). But the story of Dionysius' heterogeneous army also makes an ideal starting point to consider the many questions raised by the subject of this book: the vicissitudes of mercenaries in the ancient Greek world. This is a fascinating yet problematic topic because, as B. explains throughout, mercenaries occupied an ambiguous space in the social and cultural horizon of the Greeks. In fact, ‘ambiguity’ was the main characteristic of this heterogeneous group (p. 403). They were the quintessential outsiders, unsettled by definition. In a striking paradox, by putting themselves at the service of an employer, mercenaries were the polar opposite of the ideal of the kaloskagathos. At the same time, they excelled in the activity which more than any other defined the virtuous man: war (p. 403).

Trying to dispel some deep-rooted commonplaces on Greek mercenaries, synthesised by a famous phrase coined by Y. Garlan, pathologie sociale (pp. 23–4), B. aims to observe the world of Greek and foreign mercenaries from the perspective of their employers (p. 16). The book therefore does not follow a merely chronological pattern, but travels across the ancient Mediterranean to see by whom, why and when mercenaries were employed: the journey begins in continental Greece and visits Egypt, Persia, Sicily, Thrace and the Macedon of Philip II and Alexander the Great. The scope of this journey is to examine, from the earliest documents of the Mycenaean world to Alexander's Persian campaigns, how the development of a more articulate economic system, and the growing complexity of war-making, increased and transformed the presence of mercenaries on the battlefields of the ancient Mediterranean (pp. 22, 81). This structure makes for pleasant and vivacious reading. The main narrative of the book is juxtaposed with a series of ‘impossible biographies’ of famous Greek mercenary leaders, from Archilochus to Coeratadas and Clearchus to Dexippus.

B. argues that in the Greek world there was no ideological restraint on the employment of mercenaries in warfare: the problem was one of funding (p. 81). If hired troops were used sporadically in the years down to the late-fifth century (pp. 51–63), the outbreak of the Ionian War, the engagement of Sparta at sea and the involvement of Persia in the great conflict of the poleis brought about a radical change in this pattern (pp. 65–7). Notable consequences of this transformation were the growing interactions between Greeks and non-Greeks, and between the centre of the Greek world and its peripheries. This is an important theme of this book. For, if mercenaries are socially unsettled and marginal, the history of their role in the wars of the ancient Aegean (p. 16) is to a very large extent the story of the rise of the liminal areas of the Greek world, from Dionysius, whose campaigns highlighted the articulate relationship between employers and mercenaries, and the importance for the latter of acquiring social stability and legitimacy through the exercise of their profession (pp. 415–16), down to the battles of the Sacred Wars and the campaigns of Alexander.

Credit is due to B. for delivering a lively, engaging and provocative book, which offers an enjoyable and accessible introduction to a challenging topic without compromising on scientific rigour.