In his book Flying Tiger, Ulrich Krotz offers an intriguing empirical account of the joint Franco–German production of a military combat helicopter (the Tiger), while at the same time aiming to fill a void in international relations (IR) theory by conceptualising how inter-state relations – the Franco–German relationship in this case – are in turn influenced by domestic realities, and how this affects national interests and the security policies of states.

The book starts with two chapters that introduce the research puzzle and the theoretical framework applied in the research. Krotz convincingly argues that established IR theories fall short in explaining the inception of the Franco–German collaborative effort, the ensuing twists and turns in the cooperative endeavour, and its final success after nearly four decades. A constructivist-institutionalist alternative framework is proposed introducing ‘interstate institutionalization and construction’ (p. 29) – of which the Franco–German inter-state relations are one example – as a variable that affects national interest formation. This inter-state-level variable generates routines and common codes of conduct that shape standards of normality, legitimating some policy options while delegitimising others. Its impact on national interests and policies is expected to increase with higher degrees of state authority and state autonomy and when domestic ideas are congruent with the ‘interstate constructions’ (p. 45).

The empirical part of the book is divided into four chapters which provide an empirically rich and comprehensive analysis of the Franco–German collaborative project, based on a wealth of primary and secondary sources. Apart from exploring the explanatory power of the constructivist-institutionalist model, realist, neo-liberal and liberal alternative explanations are also duly reflected on. In doing so, Krotz identifies the added value of his model more precisely, while at the same time giving credit to existing IR theories when warranted.

Overall, the book meets its aim of providing further insights into the dynamics between inter-state relations and domestic realities and how these affect state interest formation and policy definition. Furthermore, Krotz provides a clear conceptualisation and measurement of inter-state relationships. Apart from Franco–German relations, this measurement could also be applied to other relations such as those between Britain and America. That being said, it must also be admitted that the constructivist-institutionalist model does not explicitly include broader international political considerations that may impinge on a state's national interest formation (particularly in the security domain) and further reflection is needed on the model's scope conditions. It is nevertheless a thought-provoking book for IR scholars in general and a ‘must read’ for those interested in arms procurement and Franco–German relations in particular.