In an age of information overload, H-Diplo/ISSF roundtables help you decide which books to add to your reading list and which to leave aside. Robert Mandel’s Global Data Shock is itself a book about information overload, and it does provide readers with a lot of information. For a book about strategic ambiguity, deception, and surprise, however, it may or may not be surprising that the experts in intelligence affairs gathered together here offer ambivalent reviews. All praise the relevance of Mandel’s topic, as well as his skepticism for technocratic solutions to the problem, but they also highlight numerous conceptual and empirical shortfalls. Much as policymakers continue to struggle to make sense of a flood of data in global politics, it seems we still lack clarity on these important matters.