[4] During the 1918 flu pandemic, Hoover contracted influenza, which left him with a hearing impairment that affected him for the rest of his life.

[8] Over the next year and a half, he set up a network of stations across the Western U.S. capable of guiding radio-equipped aircraft along 15,000 miles of airways.

[8] As communications chief of Western Air Express, he soon was managing a staff of 75 engineers and overseeing the purchase of over $200,000 of radio equipment.

[8] During his time with Western Air Express, he was mainly located at Alhambra, California, but also made frequent trips to the airline's headquarters in Los Angeles.

[5] Shortly thereafter, he was diagnosed with tuberculosis, and he spent 1931 convalescing, first at Rapidan Camp, then at Asheville, North Carolina.

[5] After his convalescence, he briefly returned to the airline, then taught business economics to aeronautical engineering students at the California Institute of Technology.

[9] He founded United Geophysical, headquartered in Pasadena, California, in 1935 and by 1939 he had 200 employees working in five labs perfecting the art of exploring for oil by seismological means.

[10] Hoover's hearing impairment made him ineligible to serve in the United States armed forces during World War II.

[10] While there, Hoover oversaw a substantial rewriting of Venezuela's oil laws, which would provide a model for other countries in the years to come.

[14] Owing to Secretary of State John Foster Dulles' frequent illnesses, Hoover was often Acting Secretary of State, and in this capacity made two decisions widely regarded as missteps: (1) he rejected a Chinese overture in April 1955 to negotiate agreements that could prevent war between the two countries; and (2) indecision as to whether to ship 18 tanks to Saudi Arabia in winter 1955 over the objections of Israel.

[14] By late 1956, however, Hoover was generally regarded as having learned the job, and was seen as a capable manager when Dulles was hospitalized.