I beg to disagree - I offer "Battlefield Earth" as the worst movie ever made from an awesome book.
As an aside, L. Ron Hubbard's "Battlefield Earth" is the world-wide best selling Science Fiction book of all time. Some stories do not translate to the big screen very well, this was one such book.
On many lists of the 100 best or most popular all time books, you'll find Atlas Shrugged and Battlefield Earth in the top 3. The reason is that the Rand cultists and the Scientology cultists go on massive buying sprees and massive "freeping" of book polls. An example of Hubbard cultist behavior...
Battlefield Earth went to the top of the New York Times Best Seller list and also those of the Los Angeles Times, TIME, United Press International, Associated Press, B. Dalton's and Waldenbooks. According to Hubbard's literary agents, Author Services Inc., by June 1983 the book had sold 150,000 copies and earned $1.5 million.[18] Not long afterwards, stories emerged of a reported Church of Scientology book-buying campaign mounted to ensure that the book would appear on the bestseller lists. According to newspaper reports, Church representatives promised the publishers that a particular number of copies would be bought by Church subsidiaries[19][20] (the author and journalist Russell Miller cites a figure of 50,000 hardback copies[21]). Local Churches of Scientology and individual Scientologists were reportedly also urged to buy copies of the book. Various bookstore chains (including Waldenbooks) have cited examples of Scientologists repeatedly coming into stores and buying armfuls of the book at a time. Several bookstores reported that shipments of the book arrived with the store's own price tags already affixed to them, even before they were unpacked from the shipping boxes, suggesting that copies were being recycled.[19][20] According to Miller, Scientologists throughout the United States were instructed to go out and buy at least two or three copies each.[21] Gerry Armstrong, who worked in the Church's archives at the time, states that "One of the wealthy Scientologists, by the name of Ellie Bolger, apparently paid a huge amount of money to the organization, which they then disbursed to staff members to go down to B. Dalton or whatever and buy the book."[22] The New York Times reported that "two Scientology organizations bought a total of 30,000 copies of Battlefield Earth at discount directly from the publisher, apparently to sell or to give to current or prospective Scientology members." Booksellers told the newspaper that they had seen unusual purchasing patterns, including individuals buying as many as 800 copies of the book at a time. It was suggested that "church members could be trying to buy themselves a bestseller in order to obtain a large paperback or movie sale, both of which are often contingent on a book's first becoming a bestseller in hard cover."[23