John Steinbeck's (search) surviving blood heirs are suing the estate of his third wife, Elaine Steinbeck, alleging a "30-year hidden conspiracy" to cheat them of royalties and copyright control and detailing a bitter family feud worthy of a Steinbeck novel.

The late writer's son, Thomas Steinbeck, and granddaughter, Blake Smyle, filed suit Thursday in the U.S. District Court in New York, seeking greater ownership of "The Grapes of Wrath" and other Steinbeck classics and monetary damages of at least $18 million.

"This is not a happy day for my clients," said the plaintiffs' attorney, Mark. S. Lee, of Manatt Phelps & Phillips. "This is an unfortunate but necessary step in retrieving rights my clients believe belong to them."

Defendants include McIntosh & Otis, Inc., a literary agency that handles John Steinbeck's literary estate; two sisters of Elaine Steinbeck; Elaine Steinbeck's daughter from a previous marriage, Waverly Scott Kaffaga; and four grandchildren.

McIntosh & Otis said Thursday that it had no immediate comment.

John Steinbeck died in 1968, but his books remain in great demand. "The Grapes of Wrath" and "Of Mice and Men" (search) sell hundreds of thousands of copies annually, and "East of Eden," an epic story of family rivalry, was an Oprah Winfrey (search) book club pick last year. His works are also frequently filmed and staged.

The author's literary estate was originally bequeathed to Elaine Steinbeck, whom he married in 1950. In the early 1980s, the author's sons from a previous marriage, Thomas and John IV, sued for partial control and the case was settled out of court.

The current suit alleges numerous acts of wrongdoing since that settlement, including undermining a television miniseries deal for the author's "Travels With Charley," and illegally claiming trademark rights to the author's name and likeness.

"If she stopped doing what she was doing when the lawsuit was over, we wouldn't be here today," attorney Mark Lee said.

Steinbeck's heirs personally attack Elaine Steinbeck, who died in 2003, and John Steinbeck IV, who died in 1991 and is accused of stealing personal papers from his brother, falsely claiming he destroyed them and later selling some for profit.

Elaine Steinbeck has long been admired by many Steinbeck fans, including Edward Albee, Bruce Springsteen and Julie Andrews, as a tireless champion of his legacy. But she is portrayed in the court papers as jealous and vindictive, cruelly putting distance between John Steinbeck and his two sons.

"For example, as John Steinbeck's death neared, she refused to tell Thom, who was serving in Vietnam, of his father's imminent demise," the court papers read.

"After Thom learned of his father's grave illness through an AP wire service story, he was granted permission by his commanding officer to travel home, and traveled 12,000 miles to see his father. However, Elaine refused to contact Thom as John Steinbeck was dying, even though Thom was within blocks of his father."

The lawsuit notes that Elaine Steinbeck had been an actress before marrying John Steinbeck and thus fancied herself a "theater" person. Describing a "below market" deal with a theater company for film rights to the author's "The Winter of Our Discontent," the plaintiffs blame "Elaine's personal whim and friendship" and define the transaction as merely "satisfying to Elaine's ego."

Thomas Steinbeck is himself an author whose story collection, "Down to a Soundless Sea," came out in 2002.