This timely book provides a comprehensive insight into the challenges facing humanity and Earth in the 21st century. It opens with a discussion of the domination of all the continents and oceans by a growing human population. This is followed by an appraisal of the extent to which water and food supplies will be able to accommodate this population, which may reach eleven billion by 2100. The rapidly increasing ability to change biology and evolution through genomics is considered next and complements a discussion of disease, which is viewed largely as an evolutionary struggle between humanity and pathogens. A seemingly insatiable demand for energy, future energy supplies and the impact of their use on climate and attempts to ameliorate these effects are next examined. The book concludes with a discussion of the partial destruction of the ozone layer and the international effort to repair the damage.