Bill Gates' favourite scientist is on a mission to make facts matter Is flying dangerous? How much do the world's cows weigh? And what makes people happy? From earth's nations and inhabitants, through the fuels and foods that energize them, to the transportation and inventions of our modern world - and how all of this affects the planet itself - in Numbers Don't Lie, Professor Vaclav Smil takes us on a fact-finding adventure, using surprising statistics and illuminating graphs to challenge lazy thinking. Packed with 'Well-I-never-knew-that' information and with fascinating and unusual examples throughout, we find out how many people it took to build the Great Pyramid, that vaccination yields the best return on investment, and why electric cars aren't as great as we think (yet). There's a wonderful mix of science, history and wit, all in bite-sized chapters on a broad range of topics. Urgent and essential, Numbers Don't Lie inspires readers to interrogate what they take to be true in these significant times. Smil is on a mission to make facts matter, because after all, numbers may not lie, but which truth do they convey?