When Vivek Murthy accepted the role of Surgeon General under Obama, he thought his main focus would be tackling the opioid crisis and obesity. Instead, he discovered a much larger health crisis, one that connects the sick and the seemingly well: loneliness. We live in an age steeped in disconnection. As a doctor, Murthy encountered people who struggled with addiction, disease, and pain, and often found loneliness at their very core. But while other illnesses can be more visible, loneliness keeps its sufferers silent. So how can we treat it, and what does it mean to live in this lonely age? This book traces Murthy's journey to find the answers. As he uncovers the global proportions of this epidemic, and explores the root causes and devastating effects of loneliness, he also finds good news. From social support groups in Okinawa, to mentoring circles in Chicago, he looks at community efforts to combat loneliness around the world and what they can teach us about doing so in our own lives. Part personal journey, part medical exploration, part social toolkit, this essential book shows how together we can learn to build a more connected, less lonely world.