Jared Diamond falters, weakening his central claim that prominent individuals decisively shape historical outcomes. He builds the book around a self-described "Hamlet test", a device intended to show when single figures matter, and then moves through case studies in politics, sport and business. Some passages land: Diamond argues that Botswana’s first post-independence president, Seretse Khama, uniquely dismantled chiefs' power, and he points to two wealthy Californians as the only plausible inventors of a pomegranate-juice industry that required vast upfront capital. Other sections strain under loose inference and shaky evidence.
Diamond’s Shakespeare example is emblematic. He uses William Shakespeare’s singular genius as proof of uniqueness, while downplaying Christopher Marlowe’s early death in 1593 at 29, Marlowe’s authorship of Doctor Faustus and Tamburlaine, and the possibility that Marlowe might have continued to rival or shape English tragedy had he lived. The reviewer notes that Shakespeare’s great tragedies emerged a decade later, so the counterfactual is far from settled.
The book’s methodological centrepiece is the use of "natural experiments", statistical comparisons of similar past events. Diamond invokes the 1990s work of David Card and Alan Krueger on neighbouring fast-food outlets to show how quantitative methods can overturn received wisdom. He also cites estimates that CEOs account for between 6% and 29% of earnings variation, and that coaches explain at most about 30% of a team’s performance. Those findings demonstrate the value of careful comparison, but they also expose the limits of numbers when applied to less quantifiable domains.
Problems arise when Diamond accepts proxies without sufficient scepticism. He reports studies that use UN parking fines as a stand-in for national corruption, and cousin marriage rates as a proxy for lower IQ, the latter then linked to monarchs’ territorial expansion. He misreads a 2009 paper by Benjamin F. Jones and Benjamin A. Olken on assassination, noting its conclusion that assassinations rarely alter war outbreaks while omitting that Ferdinand is excluded from their data and that the paper itself warns against that very inference. The same paper, the reviewer adds, finds that assassination in autocracies can sometimes facilitate transitions toward democracy.
The book concludes by proposing other questions for natural experiments, including when military leaders matter most. The reviewer suggests Diamond would have benefited from engaging military historians, naming Lawrence Freedman’s Command as an example. Overall, the book mixes persuasive examples with overreach, and readers should treat its big‑picture claims with caution while recognising the value of its empirical instincts.
