Does the cosmos really affect our individual lives? What is our relationship to the planets we see in the sky night at night? Scientists refer to our human existence as an insignificant accident in a vast, indifferent universe. Rudolf Steiner, on the other hand, maintains that we are intimately enmeshed with the whole cosmos, right down to the physical structure of our individual bodies. In this book, Steiner explores our relationship as individuals to the cosmos, both the physical and the spiritual, in which we will all become cosmonauts ... eventually. The key to being at home in the universe is to comprehend the real significance of our individual, physical lives on Earth and the nature of what happens once we leave our physical bodies behind. Steiner outlines his view of our journey after death as well as our return to Earth and a new life. He describes the 'planetary' spheres through which we each pass and their effects on our future. He shows us how the qualities of our character and actions here on Earth affect us after we die and how our those experiences shape our next physical life. This is not merely more information to add to our already overabundant store of abstract concepts; Steiner gives us imaginative exercises that help us explore our suprasensory, or spiritual, human nature. We can begin right now to act more consciously by taking responsibility for recognizing the concrete nature of morality and the real consequences of our present lives. This important work includes an introduction and a comprehensive afterword by Paul Margulies, a long time student and teacher of Steiner's ideas. He explains and contextualizes Steiner's text, revealing a message that is more vital and relevant than ever for our frenzied, materialistic lives. This book can help us experience more meaning in life and become more at home as spiritual citizens of the universe.