In Unfit for Purpose, biologist and broadcaster Adam Hart explores the mismatch between our fundamental biology and the modern world we have created. In each chapter Adam reveals the many ways in which biological adaptations that evolved to help us survive and thrive now work against us. For example, in the modern world stress is a killer but how did 'fight or flight' instincts turn from life-savers to life-takers? Obesity might be a disease now but is it really just a troublesome side-effect of our complex evolutionary past? Whether it's the derailing of microbes in our gut, the rise of gluten and lactose intolerance, the problems of social media or the horrors of drug addiction we always seem to have one foot in the modern world and the other firmly in our evolutionary past. By probing deep into our evolutionary legacy, exploring the science, archaeology, medicine, genetics, sociology and more, to show how, in a modern world of our own making, we find ourselves 'unfit for purpose'. But all is not lost! By unpicking the evolutionary causes of many of our current woes, it reveals some secrets of evolutionarily-informed treatments that will change the way we think about ourselves and our future.