Muggles' Guide to Harry Potter/Places/Headmaster's Office, Hogwarts

General Overview
The Headmaster's Office at Hogwarts is the office in which the current headmaster or headmistress of Hogwarts works. Although this is never mentioned, it is very likely that his residence is adjacent. It is reached by means of a circular, moving stone staircase, which in turn is concealed by a gargoyle on the third floor. The gargoyle will step aside in response to a password. At the top of the staircase is a wooden double door; the Headmaster's office is directly behind these doors.

First Six Books
As the series progresses, we gradually see more and more of the Headmaster's office, and understand its function better.

We first see it in Harry Potter and the Chamber of Secrets. Harry has just rather literally tripped over the Petrified body of Justin Finch-Fletchley. Professor McGonagall, the first on the scene, says nothing in response to Harry's pleas of innocence, except to say that it is out of her hands. She proceeds to a gargoyle in the halls, and says the password ("Sherbert Lemon"), whereupon the gargoyle leaps aside, revealing a slowly ascending circular staircase. Reaching the top of this, they find an oaken double door. They pass through this, then Professor McGonagall leaves Harry in the Headmaster's office. Harry sees that the room contains a vast number of portraits of past headmasters, all evidently asleep; many spindly tables with intricate silvery devices upon them; and the Sorting Hat resting on a shelf. After exchanging some words with the Sorting Hat, Harry notices a very ill-looking bird on a perch behind the door; as he watches, aghast, the bird catches fire. Professor Dumbledore, then entering, tells Harry that the bird, Fawkes, is a Phoenix, and that is his method of immortality; he will shortly be reborn from his own ashes. Harry and Dumbledore, though briefly interrupted by Hagrid, discuss the petrification of students that is then occurring. Dumbledore asks Harry if he has any ideas about what is going on; Harry, mindful of Ron's earlier comment that "hearing voices" was not something normal for wizards any more than for Muggles, chooses to say he knows nothing about it.

In that same book, in a memory of Tom Riddle's, Harry sees the Headmaster's office as it had been in the time of Professor Dippet, the headmaster preceding Dumbledore. At this point, Tom Riddle is seeking permission to stay at the school over the summer; Dippet refuses him, on the grounds that with the Monster from the Chamber loose, nobody's safety is assured within the school. While Harry notes that the many intricate devices and Fawkes are not present, he does not mention any of Dippet's possessions.

In Harry Potter and the Goblet of Fire, Harry again visits the headmaster's office, this time of his own volition, guessing at the password. Once within, he is interviewed briefly by Dumbledore, Professor Moody, and Cornelius Fudge, and then is left alone while the three adults visit the site where Mr. Crouch had last been seen. While alone in the office, Harry finds another artifact of Dumbledore's: a Pensieve. Dumbledore, returning, surprises him still using the Pensieve, and enlightens him as to its use, before asking why Harry had come to visit him. Harry relates the dream from which he has just awoken, in which he had perceived a discussion between Voldemort and Peter Pettigrew. Dumbledore asks for other occasions when Harry's scar had pained him, informing him that he is in contact with Sirius Black; Dumbledore also mentions that Neville's parents had been driven insane by the people Harry had seen in the Pensieve, and were now permanently in hospital.

In the same book, after the unmasking of Barty Crouch, Dumbledore takes Harry to his office again. There, with support from Sirius and Fawkes, Harry is required to recount the events of the evening, including the duel with Voldemort in the cemetery. Dumbledore seems momentarily pleased that Voldemort had used Harry's blood in his re-animation, but does not explain why. With the story told, Dumbledore escorts Harry and Sirius to the Hospital Wing.

In Harry Potter and the Order of the Phoenix, Professor McGonagall again takes Harry and Ron to the Headmaster's office, this time immediately after Harry has seen the vision of Mr. Weasley being attacked. As they approach the office doors, Harry hears a large number of voices all talking at once, but when the doors open, there is nobody there except Dumbledore himself. Over the course of the next few minutes, it becomes apparent that Dumbledore has been speaking with, and apparently receiving information and advice from, the portraits, even though they appear to be sleeping. The evidence for this is that he addresses two of the portraits, who immediately awaken, and sends them off to gather information; and wakens a third who reluctantly carries a message to Sirius Black at Number 12, Grimmauld Place. Harry also notes that many of the portraits appear to be simply pretending to sleep. Dumbledore also makes use of one of the small devices on the spindly tables, to determine something about the snake which had attacked Mr. Weasley.

Later in that same year, Professor Umbridge, having been informed of the existence of Dumbledore's Army, and with the help of her Inquisitorial Squad, manages to capture Harry and parades him in front of Cornelius Fudge in Dumbledore's office. Based on the name of the group, Fudge leaps to the conclusion that Dumbledore is raising an army to attack the Ministry, and attempts to put Dumbledore under arrest. The attempt fails, but Dumbledore does leave his office. Professor Umbridge is appointed Headmistress by the Ministry, but the Headmaster's office remains sealed to her; evidently the school itself does not recognize her authority.

When the Ministry is forced to recognize that Voldemort has returned, at the end of that book, Dumbledore is re-instated as Headmaster. Harry, sent to the Headmaster's office by Portkey, notes that the damage that had occurred in Dumbledore's abortive arrest had somehow been repaired. Dumbledore himself arrives shortly by means of Floo powder. In the ensuing, rather heated, discussion, Harry destroys one of the spindly tables and the instrument sitting upon it; Dumbledore does not seem perturbed by this. In Harry Potter and the Half-Blood Prince, Harry is called to Dumbledore's office a number of times to share memories of Tom Riddle and learn of his past. Harry notes that, instead of an instrument, one of the tables contains, at various times, artifacts of Tom Riddle's early life. Apart from this, however, Harry notes very little about the office that has not already been mentioned. The occasional comment from a portrait is generally dismissed.

Deathly Hallows
At the end of Harry Potter and the Half-Blood Prince, after Dumbledore's death, a large portrait of him, asleep, appears in the Headmaster's office. The portrait is already present when Professor McGonagall summons the Heads of House to discuss the future of Hogwarts, mere hours after Dumbledore has died, and without anyone else (as far as we know) having been in the office.

While we do see the Headmaster's office several times in Harry Potter and the Deathly Hallows, we hear very little of how the new Headmaster has changed the decor. The desk is present, the Pensieve is present, and the portraits are all still present on the walls, but of Dumbledore's instruments, or what has replaced them, there is no mention. When Harry first enters the office, after collecting Snape's memories in the Shrieking Shack, he notes that all of the portraits are vacant, and guesses that they are all in other portraits scattered around the school, keeping track of the progress of the battle. After Voldemort's defeat, the portraits are all back in residence, and give Harry a loud ovation upon his arrival.

Analysis
As mentioned, it is likely that the headmaster's office is merely the public area of his residence. We don't, of course, know where Dumbledore lives while he's at school, but the theory that he lives in a suite of rooms fronted by the office is supported by his appearance in Harry Potter and the Chamber of Secrets. There, Harry is brought into the office through the double wooden doors by Professor McGonagall; Dumbledore enters afterwards, but does not enter through these doors, instead apparently appearing from the other side of the office. We can surmise that this is common for all of the teachers at the school, that they have an office available to the school staff and students, and private rooms behind. In support of this, we can offer the Slug Club Christmas party hosted by Professor Slughorn in Harry Potter and the Half-Blood Prince; entrance is through Professor Slughorn's office, but there seem to be several rooms involved in the party.

It is, perhaps, a little strange that a password is required to reach the Headmaster's office. Of course, all the teachers must know that password, and Harry happens to overhear it when Professor McGonagall takes him to Dumbledore's office in Harry Potter and the Chamber of Secrets, so the secret is not particularly well guarded. Still, one must wonder why any protection of that nature is needed. We can only surmise that this is a remnant of earlier Headmasters, who were perhaps not as popular as Dumbledore. It is noted in one of the books that Phineas Nigellus Black was the least popular Headmaster in recent history; one can suppose that he certainly felt the need for security of his office. The password does have the effect of preventing Dumbledore from being bothered by students passing through, as he does not appear to have a secretary or receptionist to prevent anyone who reaches the door of the office disturbing him.

It is most curious that Harry, when he was only a second-year student in Harry Potter and the Chamber of Secrets, should be left alone in the Headmaster's office. This actually is a signal of the respect that Dumbledore inspires in the students; he is willing to trust that the students will not pry into areas of his office that he does not wish them to see. Harry somewhat strains the limits of this respect, by trying on the Sorting Hat on his first visit, and by investigating Dumbledore's Pensieve on a later visit.

While we see the Headmaster's office under three Headmasters, it is more often defined by what is not there than what is there. With Dumbledore in residence, Harry remarks on the many small tables bearing intricate mechanical devices. When we see the office in Dippet's time, the only difference Harry notes is the absence of the small tables and devices. And Harry is centered on the portrait of Dumbledore and the Pensieve when he visits the office after Snape becomes Headmaster, and does not notice much else about what is present in the office.

It is quite possible that Snape does not feel comfortable putting his personal stamp on what must seem to him, still, to be Dumbledore's office. While we cannot be certain, it is likely that Dumbledore was already Headmaster when Snape entered the school, and for Snape's entire 20 year tenure, first as a student, then as Potions Master, that space would have been Dumbledore's alone. Even if Snape is able to see it as his own, rather than as Dumbledore's, he has been in that office less than a year, and it is possible that he simply hasn't yet had time to personalize the office to any great extent. It is possible that Snape still holds Dumbledore in sufficient reverence that he does not feel worthy to place his own stamp upon what he must feel to be Dumbledore's home turf; supporting this theory is the discovery that Dumbledore's name is the password.

Greater Picture
In Harry Potter and the Deathly Hallows, there is no mention of Snape's portrait being present in the Headmaster's office after his death; there is also no mention of a portrait of Umbridge appearing. In the case of Snape, it could be argued that he did not retire or die in office, but rather had run away at a time when the school needed all the help it could get; as no human agent seems to be available to create these portraits, it is possible that the school does it itself, and had refused to create a portrait for a headmaster who deserted his post. In the case of Umbridge, it is quite possible that the school, as mentioned, had never accepted her as headmistress in the first place. It is mentioned that Umbridge was frustrated that she could not gain access to the Headmasters office. In particular, we can see that with assistance from Fawkes, Dumbledore can enter and depart his office without recourse to the Floo network or Portkeys, both of which can be monitored. We can also see that his office has been repaired. It is almost certain that Dumbledore returned to his office, at least occasionally, in order to do the necessary repairs, and was present often enough that the school recognized him as remaining its headmaster. It is actually possible that Dumbledore, having ensured his office was empty, returned and sealed it against Umbridge, then remained there throughout the time he was supposedly absent. He would certainly have needed to get food, but likely he could have arranged something with his brother Aberforth at the Hog's Head.

It is perhaps interesting to note the nature of the passwords used to gain entrance to the headmaster's office. During Dumbledore's tenure, it changes from time to time, but it is always the name of a sweet, either a Muggle candy like Sherbert Lemon, a magical treat like Whizzing Fizzbees, or an "unusual tastes" candy like Cockroach Clusters. When Harry has a need to get into the Headmaster's office in the final book, he finds much to his surprise that Snape has made Dumbledore's name a password. One might wonder how he explains this to his Death Eater teachers, the Carrows, but the Carrows are portrayed as being so very dense that they are unlikely to question any explanation Snape makes, no matter how far-fetched. What would be more difficult is explaining his choice of passwords to every other teacher in the school, notably Professor McGonagall, and to Voldemort on those occasions when he visits. We suggest that Dumbledore's name might be one password, and that only Snape himself, and Harry, ever use it; there could easily be several passwords, one more aligned with Snape's visible allegiance for the use of Hogwarts teachers.

Something that might be harder to explain is the portrait of Dumbledore. In fact, Snape will have had little to do with its size or placement, as we have noted: it seems to have appeared in the Headmaster's office without human intervention. However, it may have caused some comment among the Death Eaters that it is located so close to Snape's desk; in Harry's visits to the office, we gain the impression that it is the largest portrait there, and apparently accorded pride of place. We know that it is fairly close to the floor as well, as Snape is able to reach the Sword of Gryffindor which is hidden behind it, without any mention of his having to fly. Snape is, of course, still required to appear loyal to Voldemort in order to do the portrait's bidding; we must assume that he dismisses the portrait's advice if it is offered when any teacher is present. This actually is a concern, as Snape must repeatedly have conferences with the portrait of Dumbledore. Can he be certain that none of the Headmasters are carrying information to Death Eaters? Granted that no other portrait of Phineas Nigellus Black exists, and his communications are limited to Grimmauld Place and the Headmaster's office, is it even likely that he is the only headmaster who ever believed in Blood purity? Exactly how much control does the Headmaster exert over the portraits?