Ephron scripted When Harry Met Sally (1989), a film ranked at number six on the American Film Institute's list of Top Ten Romantic Comedies.

The plot is very basic. Harry Burns (Billy Crystal) meets Sally Albright (Meg Ryan), who is a friend of his then girlfriend, when she agrees to drive him from the University of Chicago to New York.

Five years later, they meet again at an airport and it turns out that they are both on the same flight. Five years on, they meet yet again, in a bookstore.

They become friends, eventually fall in love and marry. All of this is intercut by a series of faux interviews with elderly couples who describe how they met and fell in love.

If you think I've spoiled the film for you, the clue is in the title - it wasn't called When Harry Didn't Meet Sally.

Essentially, the film is about two people who could be characters in a Woody Allen-lite film. Like his films, it is studded with New York locations that suggest intellectualism, brains, civilisation, and culture.

Most of it was shot on the Upper West Side, all of which emphasises neurotic, verbal people, but not of the full-blown Allen type.

As befitting her surname, Albright, Sally is an open-faced, bright-eyed blonde.

As befitting his surname, Burns, he's a dry, mordant, cynical, pessimistic, wisecracking man with a lot of smart one-liners.

Where she is sunny and straightforward - what you see is what you get - he's both insufferable and likeable at the same time, but beneath it all, there beats the heart of a mensch, a decent, caring man.

Yet, despite the Allenesque resonances, nowhere is there any explicit mention of anybody's ethnicity or religion.

We assume (correctly) that Harry is Jewish and Sally is gentile. This is because, in part, the film is replete with a very 'in your face' Jewish humour.

When Harry Met Sally is an example of what Ephron called the 'Jewish' tradition of romantic comedy.

As pioneered by Allen, there are no built-in external obstacles in the path of true love. Rather it is the internal neuroses of the (male) protagonist that stand in the way, the sturm und drang of the relationship.

In the 'Christian' variety, in contrast, there are genuine obstacles.

Crystal's portrayal of Harry reinvented the Jewish protagonist as witty, sensitive, and sexy - a significant departure from the schlemiel Allen.

Crystal appeared normal, an everyman, but one that began to act more Jewish (even if general audiences just read him as urban, New York, possibly ethnic).

His blend of Jewish specificity with mainstream appeal paved the way for a generation of confident, self-assured, comfortable, and openly Jewish male leads such as Ben Stiller, Jerry Seinfeld, Adam Sandler and, especially, Judd Apatow's 'Jew Tang Clan' (Seth Rogen, Jason Segel, Jonah Hill, Paul Rudd and non-Jewish Michael Cera and Jason Schwartzman).

Finally, this review must end on how this film contains perhaps the greatest sequence in Jewish cinema involving Katz's deli, a salt-beef sandwich and female pleasure.

Nathan Abrams is a senior lecturer in film studies at Bangor University and is the author of The New Jew in Film: Exploring Jewishness and Judaism in Contemporary Cinema (IB Tauris, 2012).