The global doubling of human life expectancy between 1850 and 1950 is arguably one of the most consequential developments in human history, undergirding massive improvements in human life and lifestyles. In 1850, Americans died at an average age of 30. Today, the average is almost 80. This story is&8239;typically told as a series of medical breakthroughs--Jenner and vaccination, Lister and antisepsis, Snow and germ theory,&8239;Fleming&8239;and penicillin--but the lion's share of the credit belongs to the men and women who dedicated their lives to collecting good data. Examining the development of death registration systems in the United States--from the first mortality census in 1850 to the development of the death certificate at the turn of the century--Count the Dead&8239;argues that mortality data transformed life on Earth, proving critical to the systemization of
