This book uses previously unknown archive materials to explore the meaning of the term 'incapable of work' over a hundred years (1911-present). Nowadays, people claiming disability benefits must undergo medical tests to assess whether or not they are capable of work. Media reports and high profile campaigns highlight the problems with this system and question whether the process is fair. These debates are not new and, in this book, Jackie Gulland looks at similar questions about how to assess people's capacity for work from the beginning of the welfare state in the early 20th century. Amongst many subject areas, she explores women's roles in the domestic sphere and how these were used to consider their capacity for work in the labour market. The book concludes that incapacity benefit decision making is really about work: what work is, what it is not, who should do it, who should be compensated when work does not provide a sufficient income and who should be exempted from any requirement to look for it.