Stern wants the diaries returned to her estate.
In a letter to Doug Norwine, the director of music and entertainment memorabilia at Heritage Auction Galleries of Dallas, an attorney for Stern wrote that the diaries were stolen and therefore belong to him.
"On behalf of the estate, Mr. Stern hereby requests that the diaries be returned to him immediately," the attorney, L. Lin Wood, wrote in the letter Wednesday.
Norwine said he had vetted the history of the journals and believed they were legitimately obtained by a celebrity memorabilia dealer in Los Angeles before they went up for sale on eBay.
"In the absence of a judge stopping this auction, this auction will go forward," Norwine said Thursday. "After the auction we'll determine what happens. We will continue to take the high road."
The diaries, from 1992 and 1994, cover a range of topics, from Smith's love of octogenarian oil tycoon J. Howard Marshall II to concerns about her eating.
Norwine said the German businessman decided to auction the diaries after securing the publishing rights. Opening bids will start at $20,000, Norwine said, and he expects both to fetch as much as $100,000.
By Matt Slagle