Hans Jonas was a German and American philosopher whose work bridged existentialism, theology, philosophy of biology, and ethics. Born in Mönchengladbach to a Jewish family, he studied philosophy and theology at Freiburg, Berlin, Heidelberg, and Marburg, earning his doctorate under Martin Heidegger with a thesis on Gnosticism, and counted Edmund Husserl and Rudolf Bultmann among his advisors. He maintained a lifelong friendship with Hannah Arendt. Jonas left Germany in 1933 due to the Nazi rise to power, moving to England, then Palestine, where he married Lore Weiner and served in the British Army’s Jewish Brigade during World War II. After briefly teaching at the Hebrew University of Jerusalem, he moved to North America, teaching at Carleton University and then holding the Alvin Johnson Professorship at the New School for Social Research from 1955 to 1976, later serving as Eric Voegelin Visiting Professor at the University of Munich. His major works include The Gnostic Religion, The Phenomenon of Life, and The Imperative of Responsibility, the latter formulating a moral imperative to act in ways that preserve genuine human life. Influenced by Heidegger yet critical of him, Jonas shaped bioethics, environmental philosophy, and philosophical understandings of life, technology, and human responsibility, emphasizing that ethical reflection must guide human action in a technologically complex world.