Modern scientific tools can identify a genetic predisposition to cancer before any disease is detectable. Some women will never develop breast or ovarian cancer, but they nevertheless must decide, as a result of genetic testing, whether to have their breasts and ovaries removed to avoid the possibility of disease. The striking contrast between the sophistication of diagnosis and the crudeness of preventive surgery forms the basis of historian Ilana Lowy's important study.

Lowy traces the history of prophylactic amputations through a century of preventive treatment and back to a long...