India, Oct. 10 -- Would Genghis Khan have founded the Mongol empire if he were born just a few decades earlier? Would there have been an environmental revolution without Rachel Carson? And can a sports team change its winning rate just by hiring a great coach? These are some of the questions that Pulitzer Prize-winning author and scientist Jared Diamond attempts to answer in his latest book, Profits, Prophets, Coaches and Kings. While the answers are not the most comprehensive, what unfolds is an intriguing account of leaders and change-makers, amusing social experiments, and even a brief history of the pomegranate-juice industry. One may not care much about pomegranate juice, and it may not be why one reads this book, but the section does contribute to making this an enjoyable read. The primary question Jared Diamond attempts to explore in this book - "(When) Do leaders make a difference?" - is not an easy one to conclusively answer. Unlike controlled lab and test-tube experiments, there is no way to control the umpteen variables that influence success, failure and impact in real life. Unfortunately, the very meme-able thought experiment of travelling back in time and doing away with baby Hitler is just that, a meme. A social scientist, of course, cannot create multiple simulations of a world with and without Hitler and observe the results. Given this, the methodology that Diamond uses to analyse the book's key question is fascinating. Approaching the query with all the academic rigour of a scientist, he uses two methods. The first he calls the Hamlet test. It asks whether anyone other than Shakespeare could plausibly have written Hamlet; or whether, at that particular time, Shakespeare was the only person who was uniquely qualified to do so. He presents two interesting biographies of individuals who pass the Hamlet test: Seretse Khama, the first President of Botswana, and Rachel Carson, author of Silent Spring (1962), which kickstarted an environmental revolution. The other method is that of natural experiments, in which naturally occurring events are studied across a large dataset. For instance, one study examined the effect of the death of a CEO's close family member on company profits. Another explored whether the IQ of a ruler can be seen to impact the prosperity of a country. Such experiments, across sufficiently large datasets, can be treated as evidence that CEOs and kings are instrumental in the growth of a company or a country respectively. Diamond does caution against deriving conclusions from such experiments, though, and walks the reader through possible objections too. Overall, his conclusions are less compelling than those he made, for instance, in his Pulitzer Prize-winning book, Guns, Germs and Steel (1997). That work presented a fascinating explanation for why a few specific countries colonised others and not the other way round. While Guns, Germs and Steel also was criticised by anthropologists for offering simplistic answers and being too deterministic, it nevertheless managed to present an intriguing and believable viewpoint. The arguments in Diamond's latest book rely heavily on timing and luck. For instance, the CEO of a perfume company can have more of an impact than the CEO of a furnace-manufacturing company, owing to the nature of the product. Genghis Khan's military prowess would have been of much less use had he been born just a decade earlier. He was born in a fertile wet season which allowed for plenty of food and fodder, which in turn allowed him to build a strong cavalry. It would seem that while a leader may have skill, intelligence and charisma, their impact still depends heavily on timing. There is no definitive answer, which is perhaps why Diamond puts the parenthesis in the title. The more pertinent question therefore is: When, or under what specific circumstances do leaders make a difference? The book does not conclusively answer the question it sets out to answer. However, Diamond does take the reader on a meandering, intriguing, journey through politics, sports, religion and business that is full of information and provides fresh perspective on leadership....