Jared Diamond has made a career of writing books that feel like the first serious treatment of a subject that has, in fact, been treated seriously for a very long time. Profits, Prophets, Coaches and Kings continues the tradition. The question — do individual leaders change history, or would someone else have done the same job? — is genuinely interesting. The treatment is, depending on your patience for autodidactic confidence, either stimulating or maddening. The book's central analytical device is what Diamond calls 'the Hamlet test': if no plausible contemporary could have produced a given leader's achievement, that leader passes the test and genuinely made a difference. The illustration Diamond chooses is Shakespeare. The problem, as Steven Poole's review makes clear with embarrassing efficiency, is that Marlowe died at 29 having already written Doctor Faustus and Tamburlaine, and having co-written the Henry VI trilogy with the young Shakespeare. Shakespeare's major tragedies came a decade later. Diamond's test fails its own first case study before the book has found its stride. Where Diamond is more persuasive is in the case of Seretse Khama, the first president of independent Botswana, who gutted the power of traditional chiefs — a move only he could make, because he was himself the most powerful chief. This is the test working as intended: a counterfactual that holds up under scrutiny. The pomegranate-juice industry example, which establishes that you need significant capital to enter a high-upfront-cost business, earns the review's 'No shit, Sherlock' response; Diamond does not always calibrate his conclusions against how obvious they are. The book's genuine intellectual contribution, when it lands, is its use of 'natural experiments': statistical comparisons of similar situations that diverge on a single variable. The David Card and Alan Krueger fast-food minimum-wage study — comparing New Jersey and Pennsylvania restaurants across a state line after one state raised its minimum wage — is a proper example of the method working. The finding that CEOs account for 6% to 29% of variance in company earnings, and coaches for at most 30% of team performance, are interesting and defensible data points. The parking-fines-as-corruption proxy is a stretch Diamond himself doesn't examine critically enough; the cousin-marriage-as-IQ proxy for European monarchs is the kind of number that carries a lot of hidden assumptions Diamond treats as settled. The assassinations example is where methodological slippage becomes something more troubling. Diamond cites Jones and Olken's 2009 paper to conclude that Franz Ferdinand's killing didn't cause World War I. But the paper explicitly excludes Ferdinand from its dataset because he wasn't the leader of the Austro-Hungarian empire. Diamond doesn't mention this, and he also doesn't mention the paper's more interesting finding — that in autocracies, successful assassinations increase the probability of democratic transition. That's not an oversight; that's selective reading in service of a pre-formed conclusion. The book ends with a list of questions that natural-experiment methods might address, implicitly arguing that quantitative social science is the only rigorous path to answers. Diamond suggests someone might profitably investigate when military leaders make a difference, apparently unaware of or uninterested in Lawrence Freedman's Command, which addresses exactly that question from a position of deep subject-matter expertise. This is the book's core epistemic problem: Diamond treats every field he enters as a terra incognita he is the first serious explorer to visit. The real experts are simply not in his frame. The result is a book with genuine moments — the natural-experiment methodology is worth knowing, a few case studies land cleanly — wrapped in a layer of intellectual overconfidence that a good editor should have challenged hard. Diamond is a fine synthesizer when he respects the terrain. Here, he mostly doesn't.
