'Oh, we don’t worry about 'present economic circumstances’,” says the dean of an ancient Cambridge college in Porterhouse Blue: “We find they go away after 50 years or so.” There’s a moment in this history of Homo sapiens when the author takes a well-earned breath to say something similar: “The better you know a particular historical period, the harder it becomes to explain why things happened one way and not another In fact, the people who knew the period best – those alive at the time – were the most clueless of all.”. So how good a historian is Yuval Noah Harari? His scope is impressive: for him, history, as in the study of Homo sapiens, begins around 70,000 years ago, when our species of the genus Homo overcame the other species, most significantly the Neanderthal, to begin its ascent to world domination. That was when we developed speech, which enabled us to make bigger social groups than our ancestors had managed, and to organise them better. And it’s the point at which we use history to explain our past, rather than biology. Throughout his account, Harari is able to be as refreshingly clear in his discussions of biology, of evolutionary anthropology and of economics as he is of historical trends. His necessarily speculative glimpse of how religion began is effective and convincing.