Anyone who wants to grow old healthily should start early: exercise, avoid stress, eat well, because what is good for the heart is also good for the brain. What is the secret of people who have aged happily? Modern geriatrics, which researches and treats across disciplines, is devoted to this question. The photographer Karsten Thormaehlen, author of Aging Gracefully, has travelled the world for years to portray centenarians, searching for the wisdom of older people and for where and how they live. Young at Heart, edited by the geriatrician Christine von Arnim, combines medicine and photography, with interviews, portraits, essays and biographies.