The process of scientific discovery is, in effect, a continual flight from wonder.
Albert Einstein
The second half of the 20th century was truly an age of wonder for cancer screening. In 1943, when Papanicolaou and Traut1 first published reports of a new method for cervical cancer screening, cervical cancer was still a major cause of death. By the 1950s, cervical cancer screening was being performed at hundreds of centers across the country; over the following 40 years, cervical cancer incidence and mortality decreased by 60%.2 Screening for other types of cancer was introduced soon afterward (mammography in 1963, colonoscopy in 1969)—and the use of screening increased greatly. Although cures for many cancers remained frustratingly elusive, screening was attractive because it seemed reassuringly actionable: people could do their part, by either undergoing screening tests themselves or encouraging others to do so.