This book looks to existential thinkers for reasons to hope immortal life could be worth living. It injects new arguments and insights into the debate about the desirability of immortality, and tackles related issues such as boredom, personal identity, technological progress, and the meaning of life. Immortality, in some form or another, is a common topic throughout the history of philosophy, but many thinkers who consider its possibility (or necessity) give little attention to the question of whether it would be worthwhile. Recent work on the topic has been dominated by transhumanists in pursuit of radical life extension, and philosophers from the analytic tradition who argue about the dangers of immortality. This book makes the case that continental thinkers—including Søren Kierkegaard, Friedrich Nietzsche, Miguel de Unamuno, Martin Heidegger, Jean-Paul Sartre, Albert Camus, and Simone de Beauvoir—have much to offer the debate on immortality. For most of these figures, it seems possible that an unending life would not preclude the preservation of personal identity or the sorts of dangers and deadlines required to maintain something like ordinary human values and fend off boredom. The author draws connections between these so-called "existentialists" and demonstrates how they contribute to an overarching argument about the desirability of immortality. Existentialism and the Desirability of Immortality will be of interest to researchers and advanced students working on the philosophy of death and the history of existentialism.