People with serious mental illness (e.g., SMI; schizophrenia, bipolar disorder) die at a much younger age than people in the general population largely due to preventable medical conditions, like cardiovascular disease, cancer, and diabetes. Because of our collective failure to act, this mortality gap has persisted for decades and continues to worsen despite advances in the access and quality of medical care for the general population. This book looks at decades of research on people with severe mental illness (SMI) and asks two questions: Why do people with SMI die at an earlier age than those in the general population without these disorders? And, what can be done to address these deadly health inequities? Readers will come away with a better understanding of the factors that shape the physical health of people with SMI and an awareness of the interventions, programs, and policies aimed at improving the health of this underserved population. The book goes beyond the data and the numbers and presents stories of people who live, struggle, and cope with SMI and physical health problems. It also tells the stories of clinicians, researchers, and policy makers who work to address these health disparities. In these pages, we strive to balance the presentation of scientific data, case studies, and personal narrative to raise awareness and foster compassion for this overlooked public health crisis and discuss ways to solve it.