Once a cared-for patient and now a caregiver himself, Scott Williams highlights the invaluable role of informal caregivers -- those friends and relatives who, out of love, go the extra mile for patients in need. From personal care to advocacy to emotional support, informal, unpaid caregivers form the invisible backbone of health and social systems all over the world, Williams says -- and without them, these systems would crumble. "How can we make sure that their value to patients and society is recognized?" he asks.