Why and how we age are probably two of science's oldest questions, echoing personal beliefs and concerns about our own finitude. From the earliest musings of ancient philosophers to recent pharmacological trials aimed at slowing ageing and prolonging longevity, these questions have fascinated scientists across time and fields of research. Taking advantage of the natural diversity of ageing trajectories, within and across species, this interdisciplinary volume provides a comprehensive view of the recent advances in ageing and longevity through a biodemographic approach. It includes the key facts, theories, ongoing fields of investigation, big questions, and new avenues for research in ageing and longevity, as well as considerations on how extending longevity integrates into the social and environmental challenges that our society faces. This is a useful resource for students and researchers curious to unravel the mysteries of longevity and ageing, from their origins to their consequences, across species, space and time.