This state-of-the-art review on longevity focuses on centenarians, studied as a model of positive biology.

The extraordinary rise in the elderly population in developed countries underscores the importance of studies on ageing and longevity in order to decrease the medical, economic and social problems associated with the increased number of non-autonomous individuals affected by invalidating pathologies.

The relationship between causality and chance is an open discussion topic in many disciplines. In particular, ageing, the related diseases, and longevity are difficult to define as a consequence of causality, chance or both. Discussing the relevance of these different factors in the attainment of longevity, the book gathers contributions on genetic, epigenetic and phenotypic aspects of centenarians.

The 'positive biology' approach is applied to clarify the causes of positive phenotypes, as well as to explain the biological mechanisms of health and well-being with the aim of preventing and/or reducing frailty and disability in the elderly.

Calogero Caruso, formerly Full Professor of General Pathology, is Professor Emeritus  at the University of Palermo, Italy. He graduated from the School of Medicine, University of Palermo, in 1971 (magna cum laude) and obtained a postgraduate qualification in Internal Medicine at the University of Palermo (1976) and in General Pathology at University of Rome (1978). Since 1974, he has been a research assistant, assistant professor, associate professor and full professor (since 1994) at the Institute of General Pathology, and is currently in the Section of General Pathology  at the Department of Biomedicine, Neurosciences and Advanced Technologies, School of Medicine, University of Palermo. He has been the Director (and supervisor) of the Ph.D. courses in Pathobiology at the School of Medicine, University of Palermo: Biogerontology and Immunosenescence since 1998, Molecular Medicine since 2011, and Molecular Medicine and Biotechnology since 2013. He was founder and  editor-in-chief of the journal Immunity & Ageing (2004-2018), and has authored 370 publications (8485 citations), mostly on ageing, age-related diseases and longevity, indexed on Scopus (H index of 48). Last but not least, he is national coordinator (2018-2020) of a national project on longevity, funded by Italian Ministry of Education, University and Research.