United States President Herbert Hoover was a personal friend of Charles Segerstrom. He was a guest at Knowles Hill in 1936 & 1940. They corresponded frequently and some of the original letters from Hoover to Segerstrom are still here. Hoover was a professional mining engineer and author, and became the 31st President in 1929. A strong believer in voluntarism vs. government coercion, he made a name for himself with his charitable work before the Presidency and he donated his entire Presidential salary to charity.