In 2006, Hager’s book, The Hollow Men: A Study in the Politics of Deception was published. The book details a wide range of National Party internal party documents including emails which Hager stated were leaked by six National Party insiders. The documents were said to be written by the party leader Don Brash and a wide range of people associated with him. The book was initially prevented from being published when Brash obtained an injunction preventing anyone from publishing material from emails that he had written. At the time Brash was unaware that Hager had completed and was about to launch his book. However, Brash announced his resignation from the leadership of the National Party. The following day he had the injunction lifted, allowing the book to be released. The heart of the book is its descriptions of the National Party strategy discussions and the techniques the party advisors used to try to win the 2005 national elections. The thinking behind major speeches, media management, election advertising and election messages is shown in the participants’ own words. Many of the party’s previously anonymous major donors are identified and relations with them are documented. Hager assisted with the feature length documentary of the book that was released in 2008.