Loneliness is a subjective experience, different from the objective constructs of social isolation or social exclusion. It is this subjectivity that explains why one person can feel deeply lonely despite being surrounded by friends and family, and another can feel perfectly content alone – experiencing the bliss of being alone that we call solitude, as compared to the agony of loneliness. This collection of essays has been brought together to shine a light on the individuals behind the statistics, helping us to understand better who experiences loneliness, and what particular challenges they may face.