There were single girls before there was Helen Gurley Brown, and there was sex, too. But not until her 1962 manual “Sex and the Single Girl,” which debuted a year before “The Feminine Mystique,” was there a path to becoming the single girl — the freewheeling, career-centric, libidinous and unattached woman that has become a common pop-culture archetype.

But “Sex and the Single Girl” didn’t just inspire women — it also inspired screenwriters, who wrote characters into their shows that lived their lives as Gurley Brown prescribed. Her influence extended far beyond the pages of Cosmopolitan, where she edited certain editions until her death on Monday, at age 90.

Some of our most beloved characters in pop culture “owe” their storylines to Gurley Brown. Here are a few:

View Photo Gallery: Helen Gurley Brown transformed magazine into newsstand powerhouse and regarded herself as a champion of feminine power.

Peggy Olson and Joan Holloway, “Mad Men”: Helen Gurley Brown’s own life story closely parallels that of Peggy at Sterling Cooper Draper Pryce — she began her career as an executive secretary at ad agency Foote Cone & Belding, and worked her way up to becoming a copywriter. But, like Joan, she recognized that sex could be used as a means of getting ahead, writing in “Sex and the Single Girl” that any gifts or raises received for sex were a way of narrowing the pay gap between men and women.

Elisabeth Moss as Peggy Olson (Jordin Althaus/AP)

Murphy Brown, “Murphy Brown”: Like Murphy Brown, Gurley Brown was fiercely dedicated to her career, and both women were devoted to shattering the glass ceiling. In her Post obituary, Gurley Brown was referred to as ”The standard-bearer of the ‘working girl.’” They differed only on the issue of children — Murphy Brown famously became a single mother, but Cosmopolitan was Gurley Brown’s baby, and she remained childless by choice. She rarely referred to children in Cosmo.

Candice Bergen is shown with cast members from the television comedy "Murphy Brown." (Anonymous/ASSOCIATED PRESS)

The cast of “Sex and the City”: It’s a direct descendant of “Sex and the Single Girl,” and Candace Bushnell knows it — upon Gurley Brown’s death, she tweeted “This really is the end of an era.” Each of the characters in “Sex and the City” represents elements of Gurley Brown’s book, with the exception of traditional, marriage-minded Charlotte — but even she follows much of Gurley Brown’s Cosmo advice, and not just the magazine’s many tips on how to please your man. Gurley Brown preached that women should go out and live the kind of life they wanted to live — to find what they wanted, whether it was a career or love, rather than waiting for it to come to them.

Kristin Davis, Sarah Jessica Parker, Cynthia Nixon and Kim Cattrall in the film, "Sex and The City." (Warner Bros.)

Actress Mary Tyler Moore. (ASSOCIATED PRESS)

Mary Richards, “The Mary Tyler Moore Show”: The trailblazing career woman, Mary Richards was the first single female to become a central character on TV. She debuted in 1970, eight years after the publication of “Sex and the Single Girl,” and writers weren’t afraid to address topics such as wage inequality, premarital sex, marital infidelity, and homosexuality — all of which play a part in the book. Remaining single throughout the series, Mary Richards was one of the original Cosmo girls.

The cast of “Girls”: HBO’s new indie darling Lena Dunham’s show is the little sister to “Sex and the City” — another group of four single women, but this time, they’re young enough to have never known a world without Cosmopolitan and single female role models on TV.

Lena Dunham, writer, director and star of the new HBO series "Girls." (© Carlo Allegri / Reuters/REUTERS)

There are plenty of other women inspired by Helen Gurley Brown in the gallery below — and in real life. Are you one of them? Tweet what Helen Gurley Brown meant to you under the hashtag #HelenGurleyBrown, and we’ll include our favorite responses here.

View Photo Gallery: HBO’s “Girls” stars Lena Dunham as Hannah, a young woman trying to build a career in Manhattan. She joins other struggling young women in film and TV who have tried to keep up with make-it-or-break-it city living.