It was hot, clammy and claggy, in only the way New York can be in August, and I had just moved back to the city after living in London for more than 20 years. Finally unable to bear my oven of a flat any longer, I decided to explore my new neighbourhood and stepped out on to the pavement, which swam before my eyes in the heat and was entirely empty, as every other right-thinking New Yorker had either left the city or was lying prostrate in front of their air conditioner. I wandered around for as long as I could bear it before flinging myself into a little shop I barely looked at save for noticing it had a blessed air conditioner in the window.

It turned out to be the place where I would spend more time during my years in New York than anywhere else, apart from my flat (once I sorted out the cooling system, of course). Three Lives bookshop in the West Village is one of those little shops that makes people love New York: quirky, knowledgeable, impossible to pass without picking up something and always stocked with treats for the neighbourhood dogs, whose names all the staff know. If you are going to New York, I urge you to visit it.

I went in and said I loved essay books and was looking for a funny one after having finished the latest by the great Davids: Sedaris and Rakoff. Without hesitation, the man behind the counter handed me a copy of Nora Ephron's book, Crazy Salad – Some Things About Women. I took it home, started reading and soon no longer even noticed the heat.

Obviously, I was already an Ephron fan. Heartburn is one of my favourite novels and I thought I'd been pretty thorough in my reading of Ephron, having gone through all the books of hers I could find in London. But Crazy Salad is not – crazily, as it happens – published in the UK, and that is a real damn shame that someone ought to rectify, because it really shows off Ephron at her best, both as a sharp journalist and a witty essayist.

Crazy Salad is a collection of Ephron's essays about women and the women's movement in America during the 1970s (the title comes from a Yeats quote, "It's certain that fine women eat / A crazy salad with their meat / Whereby the horn of plenty is undone."). Many of the pieces were written originally for Esquire, where Ephron worked as, put simply, the female columnist, trying to resolve for the magazine's male readers that time-honoured question of what women want.

In typically honest and delightful fashion, Ephron isn't sure of the answers herself and so sets off to find out, capturing along the way the state of the women's movement with her dispatches from consciousness-raising groups, the National Women's Political Caucus, advertisements for the euphemistically named "feminine hygiene spray", Pillsbury Bake-Off competitions and the growing prominence of Julie Nixon. Some – but not all – of these subjects are so dated that reading about them is as eye-popping as encountering a shrunken head in a museum. But the writing, as it always is with Ephron, is so fresh you could smudge the ink.

I'd become increasingly interested in the American women's movement in the 1960s and 1970s during my twenties because I believed, and still believe very strongly, that you can't really understand modern feminism without knowing the history of it. And the characters from that era just sounded so fascinating: Gloria Steinem and Betty Friedan are still well known of course, but also Bella Abzug, Shulamith Firestone, Sissy Farenthold – women whose names seemed to match their personal exoticism and glamour in my imagination. I'd read books such as Gail Collins's excellent When Everything Changed, but I lacked something contemporary from that era, something written by an outsider and with a little more humour than Kate Millett's Sexual Politics and Friedan's The Feminine Mystique, not least because the latter's homophobia rather put a dampener on the reading experience.

Ephron, as she often did, provided just what I was looking for. Crazy Salad is an education but it is also a sheer delight: funny and light but with a steel rod of intelligence running through it. She taught me just how fun it can be to write a column, and what a privileged position it is to have one, and she also taught me about feminism.

One of the big lessons I took away from that book is to beware of feminism undoing itself by infighting among its women members. She deftly captures this problem in her chapter Miami, about the National Women's Political Caucus, and it's a lesson I think about every time I see women shouting at one another on the internet.

It also taught me to laugh at feminism's self-defeatingly outré reaches (while 1970s vaginal awareness groups may no longer thrive, their modern equivalents do, believe me), and to never be cowed by anyone who tells you there is only one way to be a feminist.

Ephron was a feminist through and through, and she gave one of the greatest feminist speeches of all time in her commencement address at Wellesley College in 1996. She also loved and wrote romcom films (including the screenplays for When Harry Met Sally and Sleepless in Seattle) and laughed at consciousness-raising groups in the 1970s. She knew what was important, and she didn't get bogged down in the clamouring detail. That's what made her such a great feminist, and what makes her an eternally admirable writer.

Twitter: @HadleyFreeman