In 1942, Mary Ross moved to California and took a job at Lockheed as a mathematician.

She was thirty-four years old.

She had spent more than a decade teaching mathematics and doing statistical work.

She had graduate-level mathematical training that was, by any measure, substantially beyond what most of her colleagues at entry level possessed.

She was, in the terms that engineers use, overqualified for the work she was initially assigned.

The work she was initially assigned was computational — the kind of number-crunching work that required precision and speed and a thorough grounding in applied mathematics.

At a time before electronic computers were available for routine engineering calculations, human computers — people whose job was to run calculations by hand, using mechanical calculators and mathematical tables — were essential to the engineering process.