Mildred Augustine Wirt Benson (July 10, 1905 – May 28, 2002) was an American journalist and writer of children's books. She wrote some of the earliest Nancy Drew mysteries and created the detective's adventurous personality. Benson wrote under the Stratemeyer Syndicate pen name, Carolyn Keene, from 1929 to 1953 and contributed to 23 of the first 30 Nancy Drew mysteries, which were bestsellers.

Mildred Benson was born Mildred Augustine on July 10, 1905, in Ladora, Iowa, to Lillian and Dr. J. L. Augustine. Benson earned her degree in English from the University of Iowa in 1925 in just three years. She later returned to the university, and in 1927, became the first student there to earn a master's degree in journalism.

Benson began her career selling short stories to magazines such as St. Nicholas and Lutheran Young Folks. During her college years, she worked at The Daily Iowan under editor George Gallup, and after receiving her undergraduate degree, for the society pages of the Clinton Herald.

In addition to her work with the Stratemeyer Syndicate, Benson also wrote many other series both in her name and under other pseudonyms from the 1930s to the 1950s. She ultimately wrote under a dozen names and published more than 130 books. In 1930 and 1931, Benson wrote the Ruth Darrow series. Taking flying lessons and flying her own aircraft, Ruth wins a national cross-country race, lands on an aircraft carrier, helps the Forest Service in fighting forest fires, and alerts the Coast Guard of an immigrant-smuggling scheme. The series has been highlighted as unusual for its time, for both its generally authentic aeronautical lore, and the consistent and outspoken advocacy of women's abilities and mechanical competence.

From 1939 to 1947, Benson wrote the Penny Parker books which were published under her own name. Parker was the daughter of a newspaper editor who sought to become a reporter herself, often becoming involved in mysteries and dangerous situations. Parker was modeled after both the Nancy Drew character and Benson herself, but also gave Benson creative control of the character and her stories that she did not have for the Nancy Drew series. Benson would later cite Parker as her favorite of the characters she wrote, and considered her to be "a better Nancy Drew than Nancy is."

Benson began working at the Toledo Blade in 1944, and continued there for 58 years. After the death of her second husband in 1959, Benson focused on journalism. In the 1990s, she began writing a weekly column for the Toledo Blade titled "On the Go". She continued this and writing obituaries full-time until a few months before her death.

In the spring of 1926, literary publisher Edward Stratemeyer wrote an ad looking for ghostwriters for the Stratemeyer Syndicate. Benson applied, mentioning that she had plans to move to New York City where Stratemeyer's offices were located. At his request, Benson sent Stratemeyer some of her work with which he was impressed. While vacationing, she met Stratemeyer in New York in July and was offered to undertake the Ruth Fielding series. Under the pseudonym of Alice B. Emerson, Benson wrote Ruth Fielding and Her Great Scenario. Stratemeyer credited Benson's writing for reviving sales of the Fielding series.

Syndicate ghostwriters took the outlines supplied by Stratemeyer and wrote the novel based from an outline sent to them. After her initial meeting with Stratemeyer, Benson never saw him again; the work was done through correspondence. As with all Syndicate ghostwriters, under the terms of her contract, Benson was paid a flat fee of $125 to $250 for each Stratemeyer-outlined text, the equivalent of three months' pay for a newspaper reporter at that time. Ghostwriters signed away all rights to their texts and any claim to the Syndicate pseudonym used. Writers were, however, permitted to reveal that they wrote for the Syndicate. The Syndicate protected their pseudonyms to preserve series continuity as contributors to the series came and went.