The book's first in-depth examination is of Ada Lovelace's work on Charles Babbage's proposed mechanical general-purpose computer, the Analytical Engine. Next it tells the stories of computer scientist Grace Hopper and the six original programmers of the ENIAC: Kathleen Antonelli, Jean Bartik, Betty Holberton, Marlyn Meltzer, Frances Spence, and Ruth Teitelbaum.
