On Aug. 29, the descendants of the late great American novelist John Steinbeck will begin a weeklong trial that's largely focused on two films that were never made — a DreamWorks adaptation of The Grapes of Wrath, once set to be directed by Steven Spielberg and starring Daniel Day-Lewis, and a Universal/Imagine adaptation of East of Eden.

For decades, the Steinbeck clan has feuded with each other for control of the Nobel Prize-winning fiction author's works. For a while, that meant termination notices pursuant to copyright law. There was later some issue over whether literary agents were operating without a license. Most recently, the big controversy has been interference with what Hollywood studios had in the works.

Mostly coming out ahead are those who succeeded Elaine Steinbeck, the author's late third wife, who was the primary beneficiary of copyrights in her husband's will. That includes Elaine's daughter, Waverly Scott Kaffaga, and agents at McIntosh & Otis.

On the defensive is the author's son, Thom Steinbeck, and Thom's wife Gail Knight Steinbeck who have been somewhat frustrated in attempts to score more than what a 1983 deal for royalties provided.

Last November, in the prelude to next week's trial, U.S. District Court Judge Terry Hatter Jr. issued a summary judgment decision that held that Thom had breached the '83 deal by claiming ownership of copyrights and seeking to exploit his father's works. The California federal judge also ruled that a factual dispute remained as to whether there was an "actual disruption" in the relationship with studios via alleged interference by Gail Knight Steinbeck.

Now, the dispute is headed to a jury with both sides spelling out their respective positions in trial briefs filed with the court on Tuesday. Additionally, the showdown offers at least the possibility of some big names in the entertainment industry testifying.

According to the plaintiff — the Kaffaga side — the trial is mainly about damages to be awarded for breach of contract and slander of title. They're demanding lost profits from the Grapes of Wrath and East of Eden adaptations, financial losses resulting from the way John Steinbeck's works have been impaired by false claims of ownership, and punitive damages over the way that Gail allegedly misrepresented ownership out of dislike for Kaffaga and her agents. A monetary target isn't set forth.

Kaffaga, represented by attorneys at Jenner & Block, acknowledges that the trial will also address whether defendants are held liable for intentional interference. The plaintiff points to Gail's knowledge about the film deals, the way she spoke to Imagine's Anna Culp and threatened to terminate rights for East of Eden, and how Gail and Thom entered into a confidential side deal with DreamWorks for Grapes of Wrath whereby they'd be paid $650,000.

The defendants, represented by attorney Matthew Berger, suggest it's still possible for Thom to escape being held liable for breaching contract and slandering title. They believe themselves still entitled to assert various affirmative defenses related to the way Kaffaga allegedly ratified their conduct and waived exclusive control over copyrights. The plaintiffs object here, but Thom and Gail may at least get the opportunity to demonstrate Kaffaga failed to mitigate damages. As for intentional interference, the two seem to be on the path toward disputing that "but for" their conduct, the Grapes of Wrath and East of Eden adaptations would have provided economic advantage to Kaffaga. Thom and Gail also aim to show that their conduct wasn't "independently wrongful," an element in the interference claim.

Before the trial gets started, there's some drama surrounding the witnesses to appear.

Late last month, the defendants requested trial subpoenas for a list of 16 witnesses. Ron Howard and Brian Grazer of Imagine Entertainment are on the list. So is actor-writer James Franco, who once tried to get rights to Steinbeck's Tortilla Flat. Others include 20th Century Fox chairman Stacey Snider, former Universal business affairs executive Masako Ichino, film producer Jonathan Sanger (Vanilla Sky, The Elephant Man) and Penguin Books editorial director Kathryn Court.

Kaffaga is already challenging some of these names —Howard, Sanger, Snider — as ones that the defendants already agreed not to call. As for Grazer, the trial brief asserts that his personal knowledge as to the issues at trial should be established before he appears. (At least so far, there's no objection to Franco.)

The judge has also resolved one controversy ahead of trial. The defendants attempted to preclude use of Thom's deposition because he's in poor health and suffering from short- and long-term memory loss. On Monday, Hatter rejected the motion by finding that his competency is for the jury to consider and weigh.