Well, the link never actually took you to the book; it took you to a listing of items. And the book is no longer in that listing. The link should have taken you directly to the book page. The book page link is completely unchanged from what it's always been. Amazon wants you to buy the book, I'm sure.
And by the way, Dr. Paul most certainly is going through the major publishing houses. Grand Central Publishing publishes figures from Stephen Colbert to Pope John Paul II.