Karel Schrijver is a Senior Fellow at Lockheed Martin's Advanced Technology Center in Palo Alto, California. He was trained as a stellar astrophysicist, but soon focused on the Sun as the one star that regulates life on Earth. His professional interests range from the magnetism in the solar interior and atmosphere to interplanetary space, to the environments of planets, and to the impacts of space weather on human technology. He has authored many research publications and several pieces for the general public, but this is the first book reaching beyond his daily work. He never tires from looking at the beautiful star that we live with, observed with instruments in space that capture the Sun's atmosphere in colors that cannot reach the unaided human eye. Iris Schrijver is a Professor of Pathology and Pediatrics at Stanford University School of Medicine. She is a physician with medical specialty training in both genetics and pathology, and she directs the Molecular Pathology laboratory at the Stanford Medical Center. This laboratory provides diagnostic testing for children and adults with inherited conditions and with cancers. Depending on the condition tested for, the testing helps to make a diagnosis, to establish the prognosis, to select the right treatment, and to monitor for recurrence of disease. Her research targets the causes of hereditary hearing loss and cystic fibrosis, and the development and application of optimal diagnostic methods. She has authored and edited original research articles, book chapters, and books. She is fascinated by all the connections between her world of DNA, Karel's universe, and the sheer multitude of links between them, so paramount to all aspects of life.