To the already well-laden smorgasbord of phrases used to describe modern forms of warfare—hybrid, decentralized, nonobvious, vicarious, ambiguous, gray zone, unrestricted, remote, fourth (or even fifth) generation—Andreas Krieg and Jean-Marc Rickli have added their own slice of terminology: surrogate warfare. They define this phenomenon as “the delegation and substitution of the burden of warfare, partially or wholly, to a deputy” (p. 3).

This all begs the basic question: why do we need yet another label? At first glance, it is difficult to see how surrogate warfare is distinguished from the more commonly recognized term “proxy war” (a term the authors conceptualize rather narrowly as historical Cold War–era conflicts). There is a whiff of old wine in new bottles here, yet Krieg and Rickli open up important new discussions about the nature of patron-client relations in modern war and, crucially, the calculated trade-off that states have to make between substitution and control when externalizing war fighting at the strategic, operational, or tactical level. The management of this risk is an important theme running throughout the book.

In a crowded intellectual marketplace, the authors insist that instead of trying to “complement the existing range of definitions” of similar concepts, they want to