Ageing at individual and population levels presents one of the greatest challenges to humankind as we enter this new century. Throughout the world today older adults are the fastest growing population groups. Mortality rates have declined in virtually all countries, raising the average life expectancy in the developing countries to the high 60s, and the high 70s in the developed world. Ageing is associated with an increased risk for development of chronic diseases that contribute to morbidity and mortality. It is estimated that by 2020 over two-thirds of deaths in the developing world will be caused by non-communicable diseases. This fact, along with the high levels of chronic morbidity associated with ageing in developed countries, represents a potentially overwhelming stress to health and social care systems globally. The frontiers of knowledge in relation to human ageing have been pushed back in recent years and it is to be expected that continuous progress will be made towards understanding the basic ageing processes. Further research is now urgently needed to improve our understanding of the relationship between ageing and the pathogenesis of age-related diseases in order to identify more effective means of prevention, amelioration and management of such diseases, and reduce the social and economic impacts of population ageing and the related burden of age-associated morbidity. Age-related morbidity and mortality differ dramatically in different individuals. The focus of this book is on individual differences in susceptibility to age-related disorders. Specific chapters in the book deal with age-related pathology in the brain, age-related processes in stem cells, and age-related effects on the immune system and in bone, muscle and cardiovascular tissue. Bringing together the leading researchers in the ageing field to discuss their work, this book is compulsory reading for all those interested in the biology of ageing.