In this series of meditations, Georges Canguilhem invites readers to reflect critically on modern healthcare's various rationales. He asks probing and ever-evolving questions about the relationships between doctors and nature, doctors and patients, disease and patients, as well as the dangers in dissociating these pairings. He raises issues about treatment, health, the directions and effects of scientific medicine, its lies of omission and potential traps in metaphors we use to discuss it.