John Hein, Gary, Sperm68 - It's the Power of Stern! Joan Rivers' books have seen a major surge in sales in the wake of the late comedian's unexpected passing Thursday. The 81-year-old comedian, who died one week after suffering cardiac arrest during an outpatient medical procedure, wrote 12 books in her decades-long career, and her most recent book has catapulted back onto Amazon's bestsellers’ list. “Diary of A Mad Diva,” which was released in July, topped Amazon’s “Movers & Shakers” list Friday. The list “identifies the biggest gainers in sales rank compared to twenty-four hours ago.” MOLLY RILEY/REUTERSJoan Rivers attends the gala for the Mark Twain Prize for American Humor in 2008. The hardcover edition of “Diva” experienced a stunning 64,200 percent spike in sales, which propelled the book from 1,286 to No. 2 on the online retailer’s bestsellers list.