The couple believed Clinton would do anything to advance herself, claims the book "The Truth About Hillary: What She Knew, When She Knew It, and How Far She'll Go to Be come President," the New York Post reported Tuesday.
Klein's book is excerpted in Vanity Fair and is slated to be available later this month.
Clinton's camp slammed the book, published by Sentinel, a conservative arm of Penguin books.
"Senator Clinton will always be proud to have had the support of Senator Moynihan, and wishes she still had his wisdom and counsel," a Clinton spokesman said. "Beyond that, we don't comment on works of fiction, let alone a book full of blatant fabrications."
Maura, daughter of the Moynihans, was at Clinton's side Monday at a New York fundraiser, which produced $250,000 for the senator's re-election effort.
Campus cop fatally shoots Texas student during traffic stop
Police: Sword-wielding man demanded free tacos