One day, during the reign of Covid, Sebastian Junger was home on Cape Cod, and his pancreatic artery ruptured. He had been experiencing severe pain, off and on, for a long while, but he was extremely fit, and he had an aversion to "complaining," so he hadn't acted on his worries. (How scary it is to think about bodies. One story Junger tells is about a young man experiencing headaches. He goes in for testing, and the doctors say, "You're fine." But one particular doctor has misgivings, and demands an additional test. It's this final test that helps to identify a major aneurysm near the brain--and then experts intervene at the last possible moment, while the aneurysm is in the process of rupturing .) Junger was fortunate to have his emergency during daylight hours--when the most capable doctors were available. (In NYC, people joke that you want to have your medical event during daylight, and you want to have it in Manhattan. You don't want your hour...