The Dutch Republic was at the vanguard of military innovation from approximately 1566 to 1713, at a time when warfare was almost permanent. At that time, the Dutch knew how to wage a beneficial war and not only managed to accumulate unprecedented wealth, but also achieved general economic growth. Boterbloem applies a moral approach to these facts, contrasted by the historiography: Dutch capitalism was based on indiscriminate violence through arms production and trafficking, the extension of mercenarism, slavery and war itself. Dutch capitalism therefore grew thanks to a crude violence which ignored the huge human cost that it generated. Overseas in particular, the expansion was marked not just by war with other European powers, but also by the violence inflicted on many of the colonized peoples, in some cases in a particularly stark manner, although there were also cases of negotiated relations.

Without abandoning the moral background, the author stresses certain aspects to which less attention has been paid by the historiography, such as the production of and trade in arms. The Dutch not only produced arms for their defence and for their own army, but given the quality achieved by their products and the knowledge acquired by their artisans, many businessmen saw the opportunity to export the production of armament to other places. Some, like the De Geers, set up in Sweden, where there was more abundant raw material to manufacture cannons and handguns. Others were only devoted to selling the arms produced in the Netherlands or in other places by the Dutch manufacturers. As was usual, the businesses for the production of and trade in arms were also organized on the basis of family and kinship relations, sometimes also related to government interests.

One of the points of attraction of the book is the review of the activity of the Dutch weapon producers in Holland and elsewhere, and of the commercial transactions of some families, in particular in relation to Russia, a field in which the author is a recognized specialist. The bibliography that he provides about these cases is invaluable. The arms business was not limited to wars for national defence, but rather extended to warfare in other European countries and, of course, to the defence of worldwide commercial expansion.

The expansion of violence which accompanied the military revolution of the seventeenth century meant that a large part of Dutch society made their living both in the armed forces, from all levels of officers down to the lowliest soldier, and in other activities related to armed conflict. All social groups thus benefited from the economic possibilities created by war and they all developed the capitalist spirit of seeking opportunities and increasing personal wealth. This complicates the traditional Marxist understanding of capitalists as middle-class exploiters as it argues for much greater agency among lower-class Dutch soldiers and sailors in their efforts to benefit from skills that were in high demand. In this respect, there were also many Dutch officers, soldiers and mercenaries in the armies of other European countries, seeking higher wages or the spoils of war. It is not therefore surprising that, at the time, the Dutch were identified with armed violence to such an extent ‘that violence was the ultimate expression of what it meant to be Dutch in both a religious and cultural sense’ (according to Klooster, cited on p. 123).

The moral judgement on the violence linked to early capitalism is of course very pertinent in relation to warfare and commercial expansion. Some doubts do, however, arise in this respect: should the same moral judgement be applied to producing arms for national defence, working as a mercenary and accompanying an army to seek commercial opportunities? As the book is written, all relations with armed violence are ‘dirty’, as the title suggests, and are identified with brutal forms of violence described in several passages of the book. Although in many cases, particularly in the excesses of the Dutch East India Company, it is clear that commercial profit was obtained with deliberately brutal violence, this is not the case in other areas. A generalized moral judgement is therefore indiscriminate or, at least, lacking in nuance. It would, in any case, be necessary to resort to specialists in morals for greater discernment, that is to say an interdisciplinary approach to make more refined moral considerations. It is, however, true that the perspective of capitalism based on violence is topical and that it is right to highlight it.

I do not agree with the term ‘secret’ in the title. Although there are few studies on arms production and sale, and on other issues discussed in this book, this is not due to an attempt at secrecy. These activities were well-known throughout society which, at the time, openly participated in them. The book is right to refer to them; however, it does not study their specific contribution to economic growth: an economic approach is missing. In this respect, it would be interesting to know whether the fact that the historiography has not paid attention to these matters may be because, after all, the profit from these activities was not as high as that which could be obtained from trade in general. There is, in any case, a gap in European historiography concerning the contribution of arms production to growth. Finally, it would have been interesting to offer some comparison: there are no references to other countries, which undoubtedly experienced very similar situations in those years.