The utopian dream of extending human life and achieving immortality is as old as humanity. Religions, myths, and legends transported it into the afterlife, claiming that humans were immortal once and could be so again if they met certain conditions. Closely connected to the dream of eternal life is that of health, which can be improved or possibly even restored when it fails us in old age: Lucas Cranach the Elder's painting Der Jungbrunnen (Fountain of Youth, 1546) illustrates this vision beautifully, showing very senior citizens with sagging flesh and grimaces of pain being carted to the pool and emerging rejuvenated, with firm physiques and cheerful expressions on their faces. In SF, the theme of long or eternal life (a.k.a. “Immortality SF”) has featured in countless stories, novels, and films that explore what life would be like if we could extend our lifespans by decades until mortality becomes optional, and what we could achieve if we lived longer lives. These narratives “normalize” longevity— for example, in Robert Heinlein's Methuselah's Children, and even Perry Rhodan gains “relative” immortality by means of a “Zellaktivator” so that he can plausibly guide humanity over thousands of years. In computer gaming, winning another “life” extends players’ time in virtual reality, while it ironically shortens their time outside it. Meanwhile, in the real world, while techniques to combat the signs of aging have existed for centuries (sleep, exercise, diet, vitamins, meditation, makeup), and cosmetic surgery has enhanced the possibilities in this area in recent decades, it is only lately that an industry has emerged that researches and purports to offer the key, if not to eternal life, then at least to “extreme life extension”— for example, Dmitri Itskov's “2045 initiative” or the Alcor Life Extension Foundation (cryonics).

Even if eternal life is out of reach for most of us at the moment, recent advances in genetics have made cloning humans a possibility and we could, in theory, create an exact physical copy of ourselves.