Alan SmitheeAlan Smithee is a pseudonym used by the director of a movie if he wants to disown it. A director cannot do so on his own, however, he has to get permission to do so from the Directors Guild of America, which has a number of rules for it, the most important being that it is only used when someone else (for example the editor or the studio) has changed the movie to something different than what the director intended. The pseudonym cannot be used to hide one's own failures (at least not unless someone else makes an even bigger mess afterward). It was introduced in 1967, and the first movie to use it was Death of a Gunfighter from 1969. Most of the films that used the pseudonym were low-profile, until 1997/98 the only relatively high-profile one was 1996's Hellraiser: Bloodline.
In 1997, the comedy An Alan Smithee Film: Burn Hollywood Burn was released, in which a director wants to disown a film but cannot because his real name is Alan Smithee. The publicity around this movie, and especially around the fact that director Arthur Hiller asked and got an Alan Smithee credit for it, made the Directors Guild decide to discontinue using the Alan Smithee credit. Another affair that may have played a role was the one around American History X, where director Tony Kaye asked for a Smithee but did not get it, because he had broken the rule not to publicly attack the movie, and then went on to sue the Guild over its decision (according to some, American History X was "the first great movie for which an Alan Smithee credit was asked").
After this, the Guild decided to choose a pseudonym for each case separately, rather than use Alan Smithee or some replacement all the time. The first example of such a post-Smithee pseudonym is the Thomas Lee credit for Walter Hill on Supernova from 2000; however the appearance of some new movies with Alan Smithee credits led to a rumour that the politics on this point had changed once again. However, the DGA are sticking to their stance on the matter, and it is likely that the people using the Alan Smithee name are doing so as to attack the movie, or it's makers.