When does a person qualify for protected and continuing life? At a time when technology can sustain marginal life, it is ever more important to understand what constitutes a person. What are the medical, ethical, mental, legal, and philosophical criteria that determine protectable human life? By providing a much-needed religious/philosophical context for the discussion - examining contemporary thinking on just what constitutes valuable life - Walters broadens his inquiry beyond the human to include other animals and also deals with the phenomenon of anencephalic infants, those who are born without higher brains. Searching for a measurable and humane standard of personhood, Walters looks at its current definition and declares it inadequate. He offers instead the idea of proximate personhood, with criteria for helping to determine which individuals possess a unique claim to life.