20th-century American non-fiction writers

Stanley Bruce Herschensohn (September 10, 1932 – November 30, 2020) was an American conservative political commentator, author, film director, and senior fellow at the Pepperdine University School of Public Policy in Malibu, California.Herschensohn quickly rose to prominence in the Republican Party, becoming a consultant to the Republican National Convention in 1972 and joining the Nixon administration on September 11, 1972. He served primarily as a speech writer. He left following Nixon's resignation, but served on the Ronald Reagan Presidential Transition Team and as an official in the Reagan administration.
Previously, Herschensohn had been a Distinguished Fellow at the Claremont Institute and a fellow at the Institute of Politics at Harvard's John F. Kennedy School of Government in Cambridge, Massachusetts. He had taught politics at the University of Maryland, Whittier College and at Pepperdine University School of Public Policy.

Christine Costner Sizemore (April 4, 1927 – July 24, 2016) was an American woman who, in the 1950s, was diagnosed with multiple personality disorder, now known as dissociative identity disorder. Her case was depicted in the 1950s book The Three Faces of Eve, written by her psychiatrists, Corbett H. Thigpen and Hervey M. Cleckley, upon which the film of the same name, starring Joanne Woodward, was based. She went public with her identity in the 1970s.

Ken Keyes Jr. (January 19, 1921 – December 20, 1995) was an American personal growth author and lecturer, and the creator of the Living Love method, a self-help system. Keyes wrote fifteen books on personal growth and social consciousness issues, representing about four million copies distributed overall.

Vance Oakley Packard (May 22, 1914 – December 12, 1996) was an American journalist and social critic. He was the author of several books, including The Hidden Persuaders and The Naked Society. He was a critic of consumerism.

Eleanor Clark (1913 – 1996) was an American writer and "master stylist," best known for her non-fiction accounts.

Sylvia Field Porter (June 18, 1913 – June 5, 1991) was an American economist, journalist and author. At the height of her career, her readership was greater than 40 million people.

Joseph Harold Rush (April 17, 1911 – September 12, 2006) was a physicist, parapsychologist and author. He was the first secretary-treasurer of the Federation of American Scientists, and published numerous articles and two textbooks.
Rush was born in Mt. Calm, Texas. In the 1930s his employment as a radio operator in the Dallas Police Department became a way to support his family during the Great Depression. After earning a master's degree in physics, he taught at Texas Technical College in Lubbock and at Denison University. In 1944 he joined the Manhattan Project at the Clinton Engineer Works in Oak Ridge, Tennessee. After the end of the war, he became secretary-treasurer of the Federation of American Scientists, working in Washington to secure civilian control of nuclear power.
Rush received his PhD in physics from Duke University in 1950, and moved to Boulder, Colorado, to work at the High Altitude Observatory of the University of Colorado. He joined the National Center for Atmospheric Research upon its inception, and retired in 1974.
Over his lifetime, Rush authored many articles and books, including The Dawn of Life, a book examining the origins of life on Earth, and Foundations of Parapsychology: Exploring the Boundaries of Human Capability, a textbook on parapsychology.

Ruth Hale Oliver (April 16, 1910 – October 3, 1988) was an American astrologer, astrology teacher, writer, and occasional actress.
She was born in Philadelphia to L. Stauffer Oliver, an attorney (born in New Jersey) and Margaret H. Scott (born in England). She was married to George Gercke in 1931 and divorced in 1940. She died on October 3, 1988, from natural causes at the age of 78. Oliver had one child, actress Susan Oliver.

Helen Gurley Brown (née Helen Marie Gurley; February 18, 1922 – August 13, 2012) was an American author, publisher, and businesswoman. She was the editor-in-chief of Cosmopolitan magazine for 32 years.

Benjamin Gayelord Hauser (May 17, 1895 - December 26, 1984), popularly known as Gayelord Hauser, was an American nutritionist and self-help writer, who promoted the 'natural way of eating' during the mid-20th century. He promoted foods rich in vitamin B and discouraged consumption of sugar and white flour. He rose to fame as a self-help author, popular on the lecture and social circuits, and was nutritional advisor to many celebrities.
Hauser was supported by many film stars but was often in conflict with the medical community. He promised people they could add years to their life by eating five "wonder foods": blackstrap molasses, brewer's yeast, skimmed milk, wheat germ and yogurt. He was criticized as a "food faddist" and his dieting ideas were described by medical doctors as pseudoscientific and quackery.