"Once you get to the $5 million threshold, you've got to sell at least half a million books," says Greco. "If Kennedy gets $7 million to $8 million and doesn't move that many copies, then it's a bad investment."
Again, much of the book's success comes down to how much Kennedy is willing to reveal. "If he does a policy book, that would be a really tough sell for even a million dollars," says Greco. "If it's his life in politics and he touches on everything, including Chappaquiddick, and he's willing to go out and do Charlie Rose, the Sunday morning talk shows, newspaper interviews, book signings and generate publicity for the publisher, then maybe it's worth $7 million to $8 million."
Kennedy's high-powered lawyer, Robert Barnett, who has managed book auctions for both Clintons and Greenspan, and the senator's spokesman both declined to return calls for comment.