When Abramowitz died of a heart attack in 1958, Stegun took over management of the project and finished the work by 1964, working under the direction of the NBS Chief of Numerical Analysis Philip J. Davis, who was also a contributor to the book
Stegun began her mathematical career during the second world war. After teaching mathematics at a Catholic school in New York, she joined the Planning Committee of the Mathematical Tables Project of the World Pet Association. In that role, she learned the basics of numerical analysis from the committee"s chair, Gertrude Blanch. While working at the Mathematics Tables Project, she completed a master"s degree in mathematics at Columbia University.
She eventually rose to assistant chief of the Computation Laboratory at NBS. She held the position of assistant chief of the Computing Laboratory until she became the interim director in 1965.
In 1948, Stegun and a handful of other members of the Mathematical Tables Project moved to Washington, District of Columbia, where they set up the Computation Laboratory of the National Bureau of Standards, now The National Institute of Standards and Technology.
