The life and thought of Hans Jonas are deeply intertwined, and this is not only because the variety and adventurousness of his existence gave Jonas the possibility to think problems anew. Rather, the fruitfulness of this connection relies on Jonas’s way of ‘living philosophically’; namely, of engaging in an endless effort of existential clarification and self-reflection. Witnessing the key events of the twentieth century urged him to reflect on the meaning of both existence and philosophy. Jonas’s resolute existential attitude also reverberates in his thinking, which—as we will see in the following chapters—does not develop in a linear way, but rather, grows in a spiral and dialogical connection with historic events as well as with the biographic and intellectual encounters. This explains the recursive and self-reflective nature of many of his writings, including the most openly autobiographical ones mentioned in this chapter. Moreover, the intertwining of life and thought is particularly evident in the way Jonas enjoyed his friendships: befriending others gave him the opportunity to think, which gave birth to specific topics of thought and finally developed into knowledge.