"Living in Harmony" was done to be an inexpensive episode, more than anything else. It was a way to balance out the budget for the more expensive episodes. I, personally, think it is fine, though it would have been more interesting earlier on in the run of episodes. I will take it over "Do Not Forsake Me Oh My Darling." The mystery at the heart of it is interesting, but the execution is lacking and the absence of McGoohan (off filming Ice Station Zebra) really hurts it.
I enjoy "The Girl Who Was Death" quite a bit; but, then I see it as something else....more akin to an Avengers episode. It was an unused script from Danger Man/Secret Agent, which was never quite as fanciful, but I enjoy the heck out of Kenneth Griffith and his "marshals." Looked upon as something mostly unrelated to The Prisoner, it's a bit of fun.
"Once Upon a Time" is a brilliant piece of work and I don't see how it is "unpenetrable," though I have seen it several times and picked up bits and pieces each time. It's based on regressive therapy, where a therapist adopts the role of a surrogate parent and takes the patient back through their childhood, totally immersing them in it (in some versions) to find the underlying events or patterns that led to severe trauma and dysfunction in adulthood. It requires a close relationship between therapist and subject, which is part of what makes it somewhat controversial, though it also varies greatly between therapists. There is the danger of the therapist being too close to the subject to maintain an objectivity and then determine if their therapy is healing the patient.
Within the episode, Number 2, after some conditioning of Number 6's mind, to make him more receptive to the regression, locks himself, the Butler and Number 6 in the Embryo Room, where he then regresses Number 6 to childhood, then takes him through the stages of his life, but targeting his rebellious nature and sense of self vs sense of belonging to a group. In the segment where they recreate his school years, he is brought before the headmaster because he knows some information about the "incident" in question and is interrogated. 6 sticks to his code of not squealing on others, in the face of adult authority, mirroring his refusal to state why he resigned. Later, he is in court for an auto accident and again subjected to an interrogation and the push to conform to society's demands. Same for the segment where he is in the RAF (we can assume), on a bombing mission, getting at his moral code, trying to push him to see that it is at odds with the war. The desired end result is to break down 6's resistance to questions and rebellion against Authority, to make him compliant and then turn him towards the Village's goals. In the end, though, he turns the table on Number 2 and forces him to question his own motives and orders, to the point that he becomes ineffective in his role and succumbs to the doctored alcohol. It is implied that he is killed. The Supervisor then comes to reward 6, and he demands to see Number 1, leading to the finale.
The filming of it was arduous and Leo McKern actually suffered a nervous breakdown and had to be absent from shooting for a few days, while he recovered.
The finale, "Fall Out," was never intended to give answers, as there are no answers to give, except what you conclude in your own mind, having seen the episodes and Number 6's behavior, and your own interpretations of the themes. It is meant to make you work things over in your own mind. Viewing it the first time, as the first episode of the series I ever saw, really made it confusing for me. After watching the whole thing several times, I developed my own interpretations of what's going on and why, based on some things that McGoohan has said. He basically said the series is an allegory of the Individual, in conflict with Society. At the heat of it, it is about maintaining one's individual identity, in the face of a society that is trying to reduce them to a number and make them conform like a robot, doing as told. You can couch the themes into Authority vs Freedom, Freedom vs Dictatorship, Self vs Community, Individual vs Collective , Child vs Parent or other similar conflict between Who One IS and Who Society Say One Should Be.
The pagentry of the thing, I feel, makes you eventually give up waiting for an answer to be spoon fed and start contemplating the philosophical points being made. Number 48 (Alexis Kanner) is presented as an example of youthful rebellion, the child rebelling against parental authority as they test their freedoms. Part of this is about the child establishing their place in the world and the conflict between what they want it to be and what the parent or school or society wants it to be. It is likely there because of the upheavals going on, with the Baby Boom Generation coming of age and increasingly challenging the norms of their parent's society. He represents the Alternative Culture of the period, which was fueled by that conflict and the sheer size of those going through it, after massive global conflict and its fallout. The President pretty much argues that youth must be brought to heel, taught about their responsibilities in the world and made to join it and assume those responsibilities without question. Number 6's acceptance of the youth seems to say that Society needs to listen more to the youth and help them find their place, rather than try to hammer them into a "round hole;" but, also, the "Don't knock yourself out" comment also suggests that the youth doesn't need to get all wrapped up in the act of rebellion as much as finding out who they are and what they want and articulating it and lobbying for the change they seek in their world. In that, it accepts that the youth of the time had a lot to say about how the world had been and was being run and much of it was quite valid. By the same token, violent upheaval wasn't necessarily the way to bring those changes.
Number 2 is presented as an act of rebellion by a member of the Authority, turning on that very body, in the face of rebellion. The President argues that he was disloyal and abandoned his responsibilities, while Number 2 retorts that he is a New Man, awakened to the problems within their authority, changing his views on what his responsibilities actually were. It could be likened to Daniel Ellsberg violating the security of the Pentagon Papers and providing them to the news media to reveal what was going on within the government and the execution of the Vietnam War, feeling that he had a greater loyalty to the nation, to reveal how its government had gotten lost in this ceaseless war, which was killing or physically and mentally damaging an entire generation, that was supposed to ascend to Authority over this world.
In the end, Number 6 stays true to Who he Was and his beliefs and the Village admits that he cannot be broken, because his sense of Identity is too great for them. However, they still try to seduce him over to their side, to lead them into a greater future, rather than just let him go. In part, this is the last temptation.
Number 6 then gets his wish to meet Number 1; but learns that there is no one at the center, controlling everything, it is just a reflection of himself and the darkness on the other side. Our control is within ourselves and the struggle is within, too, as much as without.
Whether or not Number 6 escapes depends on how you view his success. If you think he proved his point and won, then he escaped. If you think he was tricked and is still in the Village, then it is true. You might see it as suggesting that the struggle still exists beyond the confines we impose upon ourself, that it is more than Parent vs Child, or Student vs School, that the conflict exists in larger society, because it exists within all of us. thus, the cycle repeats itself. It is a closed loop until we become enlightened enough to resolve the conflict within ourselves and then take that outside ourselves.
Or it was all a fevered dream, while Number 6 remains in the Village, merely fantasizing it all. Or a nightmare suffered in his own home, that is was all in his mind, representing the anxieties of his life and profession.
But, that is my interpretation and that is McGoohan's point, in my eyes, that you have to work out for yourself, what it means to you.
If you look at some of the literary influences of the series, you see that many of them have no real resolution, either. Alice in Wonderland has Alice awaken to find herself no longer in the strange world, suggesting it was all a dream, until Through the Looking Glass returns her to this world. Does Alice enter the world or does she dream it? Is there a point to what happens, beyond the individual episodes within the story? People do whole doctoral dissertations trying to sort that out.
Franz Kafka's writing was an influence, especially The Trial and The Castle, the former featuring a man standing trial for unknown charges and the trial never ends, while the latter finds a man trying to gain an audience at The Castle, trying to find an avenue to do so, only to never be given a concrete answer.
Brigit Boland's teleplay, The Prisoner, features a cleric who was tortured and jailed by a fascist invader, then finds themselves jailed and interrogated by a Communist government, in an allegory of Eastern Europe (especially Poland) where those who resisted the Nazis found themselves enemies of their own country, because they hadn't been part of the Communist sphere, before. They were ideologically unsound to be heroes of the country. In the play, the cleric is impervious to the methods employed by his country's rulers, but a new interrogator starts chipping away at his religious faith,, suggesting it is more personal vanity than service to his God and he eventually succumbs to his methods.
There is a movie, called Closet Land, which covers similar ground. The movie version features Madeline Stowe as a children's writer, in a repressive state, who has been hauled out of her bed, arrested and brought in for interrogation. Alan Rickman plays the official to whom she is brought. At first, he acts surprised that she has been brought in, as there is no record of her having any revolutionary activities. He eventually says it must be a mistake and that an official apology will be given and offers her the chance to go. She then starts make criticisms, then thinks the better of it, but hesitates to leave. Rickman suggests waiting until the apology arrives. Stowe continues being beligerrent and then the chance of freedom goes away and interrogation continues. At the heart of things are the stories she wrote, about a child locked in a closet, where his dream friends come out to play. The government sees it as a subversive allegory of revolution, with cells meeting in secret, behind the government's back. He then subjects Stowe to all kinds of interrogational and torture methods, from psychological stress and sleep deprivation, to physical stress from being held in painful positions for extended periods of time. There are moments of false hope and moments where she seems to think they will kill her and torture will end, only for it to start all over. Through it all, she remains resolute and then you see how she questions her interrogator and starts turning their eye on themselves, why they participate, why they don't rebel, why they cannot touch her spirit.
In the end, you learn that the magical Closet Land is based upon being locked in a closet, as a child, and subjected to physical and sexual abuse. The magic land was a psychological escape mechanism to remove her mind from the abuse. As an adult, it provides inspiration for her stories. There is no revolutionary allegory but one of escape from abuse. However, that proves t be a rebellion against the tyranny she experienced and a model for others to escape.
The film was released in 1991 and the techniques depicted in the film were based on actual interrogation and torture techniques used throughout the world, both by repressive and some democratic regimes. In it you will find the same techniques described in investigative journalism pieces on the War on Terror, about activities at Abu Graib and the use of "extraordinary rendition" and interrogation techbniques used by the CIA and its proxies, on terror suspects, many who proved to be falsely arrested. The film was done in support of Amnesty International and the home video release included a short PSA for Amnesty International and its work and cites the example of Vaclav Havel, who had been imprisoned in Czechoslovakia, after the crushing of the Velvet Revolution. He was later released and, after the fall of the Communist regime, became the first democratically elected president of the new Czech Republic.