In Britain, where more than a thousand people receive a cancer diagnosis each day, the National Health Service has taken a measured but consequential step toward catching the disease before it takes hold. A large-scale pilot of the Galleri blood test — capable of detecting molecular signals across more than fifty cancer types — will invite 165,000 participants into a three-year study beginning in 2021. The ambition is not merely clinical efficiency, but a reckoning with one of medicine's oldest frustrations: that the cancers hardest to find are often the deadliest, and that time, more than alm