Can a disease be an idea? A theory? Does disease exist without a patient to suffer from it? In Lovers and Livers, Jacalyn Duffin provides a lively overview of the ideas around disease. She introduces philosophical theories of disease and delves into the history of two distinct afflictions – one old, one new – which serve as examples to show how applying theory can uncover surprising aspects of the medical past and present. Written with humour and compassion, and using poignant examples from Duffin's own clinical experience, Lovers and Livers is based on a series of public lectures and innovates by utilizing audience participation and a wide variety of sources including art, poetry, literature, medical journals, newspapers. Duffin's first example of a disease concept – the now possibly defunct disease of Lovesickness – had its origins in the poetry of antiquity and its demise in twentieth-century scepticism, but Duffin argues that it may not be as passé as is generally thought. The second example is the new disease Hepatitis C. Duffin demonstrates that it too stems from ancient tradition and that it has been shaped by discoveries in virology and recent tragedies in transfusion medicine, as well as by legislators, journalists, and patients. In any given time and place, coherent concepts of disease emerge from combining social, cultural, legal, and scientific preoccupations with current epistemological priorities about what constitutes clear thinking. Lovers and Livers will be of special interest to scholars of history, philosophy, and medicine, as well as many others.