== Overview ==
Defence Against the Dark Arts is a core subject, required for all students in First through Fifth year at Hogwarts. It is offered to students in sixth and seventh year, if their O.W.L. marks are good enough, and we are told that extremely good N.E.W.T. marks are required for those who wish to pursue careers as Aurors.
== Extended Description ==
There has always been a rumor circulating around Hogwarts that the class is cursed, because they cannot seem to keep the same teacher for more than one year. Because of this, Professor Dumbledore has had immense difficulty finding teachers to fill the position.
The following is a list of the Defence Against the Dark Arts instructors in the seven years of the story arc:
Professor Quirrell (died)
Gilderoy Lockhart (destroyed his own memory, by accident)
Remus Lupin (resigned after publicly outed as a werewolf)
Alastor "Mad-Eye" Moody (found to be an impostor, unmasked, "dismissed")
Dolores Umbridge (dismissed)
Severus Snape (abandoned the post at the run)
Amycus Carrow (dismissed) - taught in Harry Potter and the Deathly Hallows, while the three protagonists were not enrolled at Hogwarts.From the name of the course, we believe that the intent of the course, at least for the six years Harry is taking it, is specifically defence against Dark magic. It is, however, somewhat difficult to determine what the actual course work entails. We don't hear what is involved in this course under Professor Quirrell. Professor Lockhart's course, after a disastrous session meant to involve defence against Cornish Pixies, deteriorates into rehashes of his published, self-aggrandizing books. Professor Lupin teaches defence against natural hazards such as Red Caps and Boggarts, and in Harry's case, Dementors. Professor Moody seems to be teaching techniques of resistance against Dark wizards, while Professor Umbridge apparently teaches negotiation techniques. Professor Snape then returns to teaching defence against Dark wizards and their allies, notably Dementors and Inferi.
Based on what we can glean from this, we guess that for the first three years, the emphasis is on natural hazards, creatures which survive principally by attacking humans, while later years are normally concentrated on ever-more-powerful human-cast spells and the defences against them. Professor Moody's introduction of the three Unforgivable Curses in Harry's fourth year is out of place in this curriculum, being more properly part of the sixth or seventh year courses, but Moody explains that as being specifically at Dumbledore's request.
We note that the first three years work could also be considered associated with Care of Magical Creatures, but that course is an elective, and, Hagrid's biases aside, is clearly meant to emphasize those magical creatures that are useful to wizards, rather than those that are actively inimical.
We also note that in order to counter a curse, you must be cursed, so the lab work in this course likely involves both jinxing and protecting against jinxes. Of course there is the Muggle dictum that "the best defence is a good offence", which would lead us to believe that jinxes, hexes, and curses might well be regular subject matter for this course. In Harry's seventh year, Neville says that the "defence" part of the course name had been dropped; we suggest that the requirement for the students to handle both ends of the curse makes dropping the defence part of the course relatively easy.
== Analysis ==
In Harry Potter and the Half-Blood Prince, we learn that Tom Riddle applied for the position of Defence Against the Dark Arts teacher, but Dumbledore refused to give him the job. Ever since, the Defence Against the Dark Arts teacher has had to leave after one year due to various circumstances.
There is a bit of an apparent contradiction here, in that to the casual reader Quirrell appears to have been the Defence Against the Dark Arts teacher for some time before the first book; Fred and George indicate that he was a better teacher in previous years, but that on one of his vacations he ran into some of the stuff he'd been teaching about and had become much more easily frightened. To mesh with Dumbledore's statement that he had never been able to keep the position filled for more than one year, it has been suggested that Quirrell had taught a number of different subjects before, and perhaps done some short-term teaching of Defence Against the Dark Arts, when the supposed curse took the main teacher out of circulation. However, it is interesting that in Harry Potter and the Order of the Phoenix, when Fred and George are enumerating the fates of the Defence Against the Dark Arts teachers, they only list the four who have been there since Harry started; Fred and George, two years older, should have seen two earlier Dark Arts teachers as well, but do not mention them. Perhaps the fates of the four teachers mentioned have been more dramatic than the fates of their two earlier teachers. There is additional discussion concerning this issue in the article on Professor Quirrell.
One of the strengths of the series is that the author so adroitly avoids the need for exposition. For instance, she does not merely tell us that the position is jinxed, nor does she simply have a revolving door of teachers for this position. We can see quite clearly that there has been an ongoing problem, by the quality of the teachers that are provided to teach this course. Professor Quirrell is a stuttering, weak-willed ditherer. His replacement, Gilderoy Lockhart, is a self-promoting popinjay with no discernible skill in the subject he was hired to teach. Remus Lupin, an extremely competent teacher, is nonetheless unemployable elsewhere because of his lycanthropy. Alastor Moody, pulled out of retirement, proves to be not what he seems. Another incompetent teacher, Dolores Umbridge, is foisted on Hogwarts when Dumbledore is unable to fill the position himself. All of these are shown to us before we are told more than rumours of the curse on the position, and quite clearly show the effects of the curse, so that when we are told of its probable existence, we simply accept it as Dumbledore apparently has.
Another editor has wondered why Alastor Moody did not return to teaching the course. It is actually uncertain whether he ever actually accepted the teaching position, or whether it was offered to the impostor; while we know when Moody was overpowered, we don't know when the offer to teach the course at Hogwarts was made. (In fact, we don't even know who made the offer; by the start of the fourth book, Dumbledore was clearly already having significant trouble finding teachers for that post, and he could have been quite relieved when the false Moody offered to teach for a year.) In any case, after having been held prisoner for the better part of a year, it's unlikely that the real Moody would have been in any shape to teach.
== Questions ==
Did Voldemort actually curse the Defence Against the Dark Arts teaching position, or is it just a coincidence?
Who is most likely to become Defence Against the Dark Arts professor after the War ended?
== Greater Picture ==
In the sixth book, Harry Potter and the Half-Blood Prince, we hear the reason for the belief that the position is cursed. After Harry and Dumbledore see Dumbledore's memory of Tom Riddle's job application, Dumbledore remarks that since that time, he has never been able to keep a Defence Against the Dark Arts teacher for more than a year. This is, perhaps, why he has resisted, up until this year, Severus Snape's repeated requests to teach this course. Having had ample demonstration that the position of Dark Arts teacher is a doomed one, Dumbledore chooses not to place Snape in that position as he is too valuable to risk. In this book, however, we learn that Dumbledore is aware that his own time is strictly limited, and so, having extracted a promise from Snape that he would "take care of my school", Dumbledore places him in that position. Dumbledore, recall, receives his fatal injury in early July, and knows that he will have at most a year to live. By requiring Snape to take the headmaster's position after his death, Dumbledore has limited Snape's term already, and likely believes that this will partially avoid the curse. Also, having arranged that Snape will kill him so as to prevent Draco from being forced to commit murder, Dumbledore knows that Snape will likely have to flee Hogwarts, thus ending his tenure in a suitably cursed manner. As Snape will have to depart the position at the end of the year anyway, Dumbledore now feels it is safe to grant Snape that position.
In Harry Potter and the Deathly Hallows, the seventh book, we learn from Neville Longbottom that under the influence of Snape and the other Death Eaters at the school, the "Defence" part of the course has now been formally dropped, and the course is the study of the Dark Arts with the object of perfecting their use, rather than defending against them. As practice, Neville says, students are required to use the Cruciatus curse against those students who are in detention.