The provided text is an excerpt from the second edition of Exploring Disability: A Sociological Introduction by Colin Barnes and Geof Mercer, which examines the transition from an individual medical view of disability to a socially-oriented perspective. The authors trace how disabled activists and scholars challenged the traditional "personal tragedy" model, which focuses on biological deficits, by highlighting the systemic social and environmental barriers that cause exclusion. Central to the work is the distinction between impairment, defined as a physical or mental condition, and disability, which is described as the oppression imposed by a society that fails to accommodate human diversity. The text explores various academic frameworks, including functionalism, interactionism, and post-structuralism, to analyze how identity is shaped by medical labels and institutional control. Furthermore, it outlines the book's broader scope, which includes topics such as independent living, media representation, global development, and the ethical implications of biotechnology. Ultimately, the source serves as a critical review of the sociological themes and political movements that have redefined disability as a matter of human rights and social justice.