Lyon Sprague de Camp was born on November 27, 1907 in New York City to Lyon and E. Beatrice (nee Sprague) de Camp. He seemed destined as a young man for a career in the applied sciences. In 1930, he received his bachelor's degree in Aeronautical Engineering from the California Institute of Technology, and in 1933, he received his master's degree in engineering from the Stevens Institute of Technology in New Jersey.

During World War II he was an assistant mechanical engineer at an aircraft factory, and he served as a Lieutenant Commander in the United States Naval Reserve. Even his first book was a technical one,Inventions and their Management (1937 coauthored with Alf K. Berle; revised as Inventions, Patents, and Their Management, 1959).

His first short story "The Isolinguals" (1937) gave a hint of the career to come. This began his relationship with two famous periodicals edited by John...