Athanasius Kircher, the eminent 17th-century German Jesuit professor of mathematics at the Roman College emerges as a captivating figure within the pages of this monograph by Agustín Udías. Aptly deemed 'the man who knew everything,' Kircher's thirty-two comprehensive works, spanning an array of subjects, provide a unique lens into his visionary perspectives. This book delves into three selected works where Kircher unveils his conceptualization of the Earth, termed the 'Geocosmos,' treated magnetism as a cosmic and spiritual force, and embarks on a cosmic exploration from Earth to the stars. From his groundbreaking speculations on the Earth's interior, attributing earthquakes and volcanoes to intricate channels of air, water, and fire, to his cosmic journey accompanied by the ethereal spirit Cosmiel, Kircher's enduring allure persists. Despite variance from contemporary knowledge, situated at the beginning of modern science, Kircher's proposals of the structure of the Earth's interior, cosmic magnetic theories, and space journey to the stars offer a compelling glimpse into the intellectual landscape of a bygone era, making this book an essential exploration for scholars seeking a nuanced understanding of Kircher's profound influence.