The current strike by Hollywood writers highlights the role of the screenplay as the foundation of a movie. Movies tell a story, and Blake Snyder, the author of books on screenwriting, says they often tell the same story again and again. The writer spoke with VOA's Mike O'Sullivan about his recent book, Save the Cat! Goes to the Movies.

"It's a classic moment in lots of movies," said Blake Snyder. "You see it when we meet the hero of the movie for the first time, and the hero does something nice, like save a cat, that makes us like him and want to go on the journey with him."

Snyder says a journey can take different forms, but there are just a few basic stories.

He calls one Monster in the House. An evil force terrorizes a small community, and he says the force is often unleashed by a human sin or failing. Jaws, the tale of great white shark that terrorizes the coastal town of Amity, fits into the category.

"It will attack and devour anything. It is as if God created the devil and gave him jaws!"

Snyder says the evil in this film was unleashed by the greed of city leaders.

"It's the sin of greed that brings the monster, Jaws, the shark, into Amity," he said. "They want to keep the beaches open, regardless of the danger."

He says Alien, a tale of an extraterrestrial monster, also fits into the category. Fear and greed expose the spaceship crew to an alien parasite.

Snyder says Fatal Attraction, a cautionary tale about the dangers of adultery, has a similar theme. The film stars Michael Douglas as a philandering husband, and Glenn Close as the crazed woman who stalks him.

FILM CLIP - GLENN CLOSE: "I guess you thought you'd get away with it. Well, you can't.

SNYDER: "Michael Douglas commits the sin of infidelity, brings the monster, Glenn Close, to his home, a monster with a perm. It's the same basic story template."

There are superhero stories in both films and classic literature. The best, says Snyder, involve a transformation as the hero finds an authentic identity or mission.

"We love to hear about his story, Moses and Joan of Arc and Spider-Man," said Snyder. "Someone has come to save us, and very often we're not necessarily grateful for them to be here."

He says the best heroes are flawed, but are guided by faith in their mission, and in movies they triumph. Evil characters generally rely on themselves, and their pride leads to their downfall.

Snyder is one of many in Hollywood who write or co-write screenplays. Some will make it to the screen, and even those that do not can be profitable. Snyder has sold a screenplay to Steven Spielberg and others to Disney.

He says Hollywood screenplays like his often describe a journey, a theme that goes back as far as the ancient Greek story of Jason in search of the Golden Fleece.

"It's about a trip," he said. "Jason has been assigned to go get the Golden Fleece, so he gets together a team of guys and off they go on these many adventures. At the end of the journey, there's a twist. It wasn't really about the Golden Fleece. It was about how Jason became a leader of men."

War films such as Saving Private Ryan or The Dirty Dozen follow this pattern. So does the heist film Ocean's Eleven and the fantasy trilogy, The Lord of the Rings.

There are films that describe friendship that follow predictable plot lines, stories of fools who triumph, and of detectives who get too close to the evil they are pursuing.

Snyder says film-goers are like children who love to hear the same stories again and again, as long as the stories are told in a new and fresh way.