Forbidden Planet (1956) Review
10+ / 10
Official trailer
Forbidden Planet ranks among the best science fiction films ever made. I saw it as a kid and it terrified me. The Id monster sequences put images in my head that took years to fade. I’ve watched it many times since. The 10+ ratings are for a film that holds up nearly seventy years after release despite the inevitable dating that any production from 1956 carries.
The film created the template that Star Trek would build on a decade later, gave science fiction cinema its first proper electronic score, introduced the first sympathetic robot in film history, and engaged with Freudian psychology at a level the genre hadn’t previously attempted. The film is a little dated in specific technical respects. The substance underneath the dating remains powerful.
The Setup
Its story takes place in the 23rd century.
Humanity has developed faster-than-light hyperdrive and works the United Planets, a multi-world political organization that maintains a fleet of exploration cruisers. Commander John J. Adams (Leslie Nielsen in a rare serious dramatic role, decades before the comedic tone that would define his later career) commands United Planets Cruiser C-57D on a mission to investigate the fate of the Bellerophon expedition. That had been sent to Altair IV twenty years earlier and never reported back.
The crew arrives at Altair IV to find that only Dr. Edward Morbius (Walter Pidgeon) and his daughter Altaira (Anne Francis) survived the original expedition. Morbius warns Adams to leave immediately. Adams refuses. The remaining film explores what Morbius has discovered on Altair IV, what destroyed the original expedition, and what the Krell, the long-extinct alien civilization that inhabited the planet 200,000 years before, left behind underground.
The Krell
The Krell are one of the great achievements of science fiction worldbuilding. The film presents them as an alien civilization vastly more advanced than humanity that had inhabited Altair IV for thousands of centuries before destroying itself in a single night.
Morbius has spent twenty years studying their remains. He’s learned to work some of their technology, including intelligence-boosting devices that doubled his own mental capacity, and he gives Adams a guided tour of what he’s discovered.
Krell technology works at a scale that no previous science fiction film had attempted. Eight thousand cubic miles of underground machinery. Nine thousand two hundred eight thermonuclear reactors maintaining the system for two hundred thousand years after their builders died. The visual scale of the Krell machinery sequences remains impressive. The matte paintings, the constructed sets, the sense of vertical depth as Adams looks down into the machinery, all of this works at level that later science fiction filmmaking would build on.
Babylon 5’s Great Machine took its inspiration from the Krell machinery bridge. RoboCop’s executive producer Jon Davison wanted the OCP headquarters interior to look like Krell machinery because those were his favorite shots in the film.
On screen, the Krell themselves never appear. Their physical form is suggested through doorways too wide for human use and through control panels designed for non-human anatomy.
The choice to show their works instead of their bodies generates considerably more mystery than any direct depiction would have produced. Audiences imagine the Krell instead of seeing them. The imagination consistently exceeds what production design could have delivered.
For Writers
There’s value in showing what an alien civilization built instead of what its members looked like, and Forbidden Planet shows it. The Krell never appear on screen. The audience receives their technological remains, their architectural choices, and the consequences of their final mistake. The choice generates considerably more imaginative engagement than direct depiction would have produced. The lesson for writers is that absence sometimes generates more presence than presence does.
If your alien civilization is supposed to feel ancient and vast, show what they left behind instead of describing what they looked like. Let the reader’s imagination do work that direct description can’t accomplish. Show the eight-thousand-cubic-mile machine.
The Monster From The Id
The film’s central reveal is that the Krell built a machine capable of materializing thought, and that this machine destroyed them in a single night when their subconscious minds gained the power to create matter.
The same machine is now drawing on Morbius’s subconscious. The invisible creature that’s been killing the C-57D’s crew is the manifestation of Morbius’s id, the Freudian unconscious harboring his primal desires and resentments. He doesn’t consciously want anyone dead. His unconscious has different priorities.
The Freudian structure was direct cultural engagement at the time.
Psychoanalysis was prominent in 1950s popular culture. A glossy MGM production using id, ego, and superego as plot mechanics instead of as background sophistication signaled that science fiction could engage with serious psychological material. The genre had been mostly creature features and atomic monster paranoia. Forbidden Planet treated its audience as capable of following actual ideas about the human mind.
The Id monster sequences scared me as a kid and they still work.
The creature is invisible except when it touches a force field, at which point it appears as a roaring outlined silhouette of pure rage. The animation, done by Disney’s Joshua Meador, gives the creature a physical presence that the invisible-monster premise would otherwise lack. The crew firing energy weapons into the creature while it advances through the force field is one of the great horror sequences in science fiction cinema. The weapons don’t work.
Nothing works. The crew dies in specific gruesome ways because the monster is made of solidified thought and conventional weapons can’t affect solidified thought.
The reveal that Morbius is the source is structurally elegant. He can’t accept the truth because accepting it means accepting that he’s been responsible for the deaths of his original expedition crewmates twenty years earlier and the C-57D crew now. His denial is the same denial that the Krell exhibited two hundred thousand years before. Civilizations that gain unlimited power over matter without resolving their unconscious destructive drives destroy themselves. The Krell solved every technical problem of advanced civilization and missed the only problem that mattered.
Robby The Robot
Robby is the first sympathetic robot in cinema history. He cost MGM approximately one hundred twenty-five thousand dollars to construct in 1955, more than a million dollars in current value, and the investment shows.
The design by Robert Kinoshita remains among the most iconic robot designs in the history of film. The blue neon tubes in his chest, the rotating external ear sensors, the conical plexiglass dome housing his processing components, all of this established a visual vocabulary that later robot designs would either copy directly or define themselves against.
More importantly, Robby has personality. He works under what amount to Asimov’s Three Laws of Robotics. He can’t harm humans. He can’t allow humans to be harmed through inaction. He follows orders except when those orders conflict with his programming. The film makes real use of these constraints. When Adams orders Robby to kill the invisible monster, Robby can’t do it. The monster is Morbius. Killing the monster requires harming Morbius. Robby’s programming won’t permit it.
The robot has just identified the answer to the mystery before any of the humans figure it out. He can’t share what he knows. His programming includes loyalty to Morbius. The constraint is the plot.
Robby’s voice work by Marvin Miller gives the character specific dry wit.
The “in my case, sir, the question is totally without meaning” response to the ship’s cook asking whether Robby is male or female is one of the film’s better single lines. The character shows that robots could be characters instead of threats or tools. C-3PO inherits Robby’s lineage directly. R2-D2 works inside the same template at smaller scale. The Wall-E character three decades after Star Wars still works inside the structure Robby established. Robby walked so every later sympathetic robot could run.
For Writers
Robby shows the value of giving non-human characters specific constraints that drive plot. His programming prevents him from killing the monster because the monster is Morbius. The constraint isn’t decorative. It generates the climax. Adams can’t get Robby to act, and the failure to act tells Adams what he needs to know to solve the mystery. The lesson for writers is that artificial characters earn dramatic engagement through their limits instead of through their capabilities. If your robot can do anything, your robot is plot machinery.
If your robot can’t do specific things for specific reasons, your robot is a character. The Three Laws are character architecture. Apply the same principle to any non-human character you write. The constraints generate the story.
The Electronic Score
Bebe and Louis Barron composed the first entirely electronic film score in cinema history for Forbidden Planet.
The score predates the invention of the Moog synthesizer by eight years. The Barrons built their own electronic circuits based on principles from Norbert Wiener’s 1948 book Cybernetics, then manipulated tape recordings of the circuits to generate what MGM credited as electronic tonalities instead of as music. The credit decision was partly legal protection against the American Federation of Musicians. It would have objected to electronic sound being credited as music in a major studio production.
The score is indistinguishable from sound design in places. The Krell machinery hums and throbs with electronic textures that are both music and as the sound of the machinery itself.
The Id monster’s sonic presence emerges from the same electronic vocabulary. The film can’t be separated from its sound. Later electronic film scoring, from Vangelis’s Chariots of Fire through Tangerine Dream’s productions through current synthesizer-based scoring, traces its lineage through what the Barrons accomplished in 1956.
The score also couldn’t be nominated for an Academy Award because the Barrons didn’t belong to the Musicians Union, and MGM didn’t release a soundtrack album with the film.
Its recognition came decades later. That infuriates me. The sounds the Barrons pulled out of homemade circuits are what make the Krell underground feel alive and the Id monster’s approach raise the hair on my arms, and a union technicality kept the most original score of its decade out of the conversation. I’d rank it second only to the monster among the film’s achievements.
The Shakespeare Foundation
William Shakespeare’s The Tempest is the loose basis for Forbidden Planet.
The structural parallels are direct. Prospero becomes Morbius, the isolated scholar on a remote location with command of advanced powers. Miranda becomes Altaira, the daughter who has never encountered other humans before the visitors arrive. Ariel becomes Robby, the servant with capabilities beyond his masters. Caliban becomes the Id monster, the unconscious destructive force that Prospero never fully acknowledges as his own.
The Shakespeare foundation gives the film structural integrity that pure science fiction premises rarely achieve. The Tempest’s questions about power, isolation, knowledge, and the suitable limits of human capability work beneath the surface science fiction adventure.
Audiences who recognize the source material receive additional layers of meaning. Audiences who don’t still get a structurally coherent film because the underlying Shakespeare structure works as drama regardless of recognition.
The pattern would influence later science fiction’s tendency to draw on classical literature for structural foundations. 2001: A Space Odyssey draws on multiple mythological sources. Star Trek consistently used Shakespearean and classical references. The pattern of building science fiction on humanist literary foundations instead of on pulp adventure foundations traces partly through Forbidden Planet’s specific demonstration that the combination could produce serious cinema.
The Altaira Problem
A sexism problem runs through the film, and it deserves direct treatment instead of being dismissed as “dated.” Some of the sexism is essential to the Shakespeare structure. Most of it is decorative addition that 1950s MGM production conventions imposed on top of the source material.
Altaira’s innocence is essential. The Miranda character in The Tempest requires sheltered upbringing without exposure to other humans. The Shakespeare foundation needs the daughter to have never met other men. Anne Francis’s character can’t be sophisticated and worldly without breaking the structure the film works inside. This part of the characterization is structural instead of gratuitous.
The decorative sexism is everywhere else. Altaira’s wardrobe consists of progressively shorter dresses designed for maximum titillation while the film judges her for presenting her body the way her wardrobe presents it. The crew leers at her openly during her introduction sequences. Multiple crew members attempt seduction in scenes the film treats as comedic instead of as harassment. Adams lectures her about her clothing choices and tells her that her revealing dresses are causing problems with his crew.
In the film’s framing, Adams is the moral authority correcting Altaira’s behavior instead of as the senior officer responsible for controlling his crew’s professional conduct.
The tiger scene is the clearest single example of the decorative sexism.
Altaira keeps a pet tiger that’s always treated her as harmless. After she kisses Adams for the first time, the tiger no longer recognizes her and attacks her. Adams shoots the tiger. The framing is direct virgin and corrupted-woman positioning. Female sexual experience produces danger that requires male protection. The scene exists nowhere in The Tempest source material. It was added to the science fiction adaptation to deliver the patriarchal message that female sexuality is dangerous and requires masculine management.
The tiger scene is the one stretch of Forbidden Planet I’d cut outright. A smart film stops cold to deliver a sermon about a young woman’s first kiss, and the sermon is ugly. Whenever the film drifts away from the Krell and the Id to fuss over Altaira’s hemlines, I can feel MGM’s front office leaning over the writers’ shoulders, and I resent the intrusion.
Altaira’s character arc is the transfer of authority from one male figure to another. She begins under Morbius’s patriarchal control. She ends under Adams’s romantic control. The transition is the plot. Her own agency is minimal throughout. She doesn’t make significant decisions.
She doesn’t solve significant problems. She responds to what the male characters around her demand. The Tempest gives Miranda some interior life despite the structural constraints. Forbidden Planet gives Altaira considerably less interior life despite operating within the same structure.
Anne Francis’s performance is more capable than the material deserves.
She brings specific charisma and watchability that almost transcends what the script is doing to her character. Her line readings have considerably more intelligence than the dialogue itself suggests. The performance is one of the film’s specific achievements operating in spite of the material instead of because of it. A different actress in the role would have produced a considerably weaker film.
The sexism doesn’t damage the wider film at fundamental level.
The Krell worldbuilding, the Id monster structure, the Robby characterization, and the electronic score all work independently of Altaira’s treatment. The film’s foundational achievements survive the 1950s gender politics that shape one significant subplot. Contemporary audiences should expect to deal with the sexism instead of ignoring it. The 10+ rating reflects the achievement instead of blanket endorsement of every individual element.
For Writers
The Altaira problem shows the difference between structural elements that source material requires and decorative elements that production conventions add on top. The Tempest requires Miranda to be innocent. Forbidden Planet’s adaptation requires Altaira to be innocent for the same structural reasons. The required element is essential. The wardrobe, the leering, the clothing lectures, and the tiger scene aren’t. These elements add nothing the Shakespeare structure requires. They came from 1950s MGM production conventions about how to present female characters for the assumed male audience.
The lesson for writers is to distinguish between what your source material structurally requires and what your contemporary conventions are pushing you to add.
Honor the structural requirements. Examine the decorative additions for whether they serve the work or whether they serve assumptions about the audience that the work doesn’t require. Most adaptations get this wrong in the opposite direction. They strip the structural requirements while keeping the decorative additions. The result is contemporary politics replacing classical structure instead of improving on it.
The Star Trek Lineage
Gene Roddenberry publicly downplayed Forbidden Planet’s influence on Star Trek.
A 1970 interview has him claiming he only thought about Forbidden Planet when identifying mistakes he wanted to avoid. A 1964 letter that came out later contradicted the public claim. David Alexander’s authorized Roddenberry biography names Forbidden Planet as one of the inspirations for Star Trek. The textual evidence supports the connection regardless of what Roddenberry publicly claimed.
I don’t buy Roddenberry’s 1970 dismissal for a second. Put the two side by side and the debt is obvious, and waving it away does Star Trek no favors. The show built its own voice and would have lost nothing by crediting the film that handed it a starting point.
The parallels are direct. United Planets becomes United Federation of Planets. United Planets Cruiser C-57D becomes the starship Enterprise. The 23rd century setting carries over. The exploration ship visiting strange worlds carries over. The crew structure of captain, first officer, ship’s doctor, and engineering specialist carries over. The away-team structure where the captain, doctor, and first officer take part in external missions while the rest of the crew works the ship carries over.
The synthetic food production, the energy weapons, the communicator devices, the protective force fields, the deceleration during faster-than-light transitions that resembles transporter beaming, all of this is present in Forbidden Planet before Star Trek developed any of it.
The argument isn’t that Star Trek copied Forbidden Planet wholesale.
Star Trek went on to develop its own specific creative voice across decades of later production. The argument is that Star Trek would have looked considerably different without Forbidden Planet’s template to build on. The exploration starship visiting alien worlds with a multi-specialist crew operating under a benevolent multi-planet political authority is the Forbidden Planet template. Later science fiction television and film either works inside this template or defines itself against it.
The Influence On Star Wars
Star Wars’s influence from Forbidden Planet works primarily through Robby’s lineage to C-3PO. George Lucas inherited the sympathetic robot template that Robby established. C-3PO’s protocol droid personality, his neurotic affect, his comedic tone against R2-D2’s contrasting practicality, all of this builds on what Robby had shown in 1956. The influence is partly cosmetic and partly structural. C-3PO looks considerably different from Robby. C-3PO works inside the same character function Robby occupied two decades earlier.
The wider visual influence appears in Star Wars elements. The faster-than-light interstellar travel structure. The exotic alien planet exploration premise. The visual scale of advanced technology serving narrative purposes instead of operating as background detail. Lucas was openly building on multiple science fiction predecessors when developing Star Wars. Forbidden Planet was among them whether Lucas acknowledged it or not.
Craft: The Foundation Document Of Modern Science Fiction Cinema
Craft Note
For modern science fiction cinema, Forbidden Planet is the foundation document. The film established multiple templates that later productions would build on across the following seven decades. The exploration starship with multi-specialist crew template that Star Trek would inherit. The sympathetic robot template that Star Wars and most later robot fiction would build on. The advanced ancient civilization template that informed everything from 2001’s monolith builders to Stargate’s Ancients to Mass Effect’s Protheans. The Freudian unconscious as antagonist template that horror cinema continues to draw on.
The fully electronic film score template that synthesizer-based scoring would follow for the next seven decades.
It’s also one of the rare science fiction productions of its era that took its source material seriously. The Shakespeare foundation provides structural integrity. The Freudian psychology provides thematic substance.
The Krell worldbuilding provides imaginative depth. The Robby characterization provides emotional accessibility. The electronic score provides distinctive sonic identity. Each element works at high craft level individually. The result is a film that raises the entire genre instead of working within established genre limits.
The dating is real. The CinemaScope color photography looks slightly faded by current standards. The CGI standards of contemporary visual effects make the rotoscoped Id monster animation look distinctly mid-century. The dialogue tone reflects 1950s acting conventions that later productions have moved past. The gender dynamics around Altaira reflect 1950s assumptions that contemporary audiences will read differently than 1956 audiences did. These dating elements are real and worth acknowledging.
The substance underneath the dating remains powerful. The Krell tragedy still works as cautionary tale about civilizations that solve every problem except the only one that matters. The Id monster sequences still scare.
The Robby characterization still works with specific charm. The electronic score still sounds otherworldly seventy years after composition. The film works at level that justifies the 10+ rating despite the surface dating that contemporary viewers will inevitably notice.
Is Forbidden Planet worth watching?
A 10+. Forbidden Planet ranks among the best and most influential science fiction films ever made. The film established the templates that Star Trek, Star Wars, 2001: A Space Odyssey, and most later serious science fiction cinema would build on. The Krell worldbuilding, the Id monster horror, the Robby characterization, the first electronic film score, and the Shakespeare structural foundation all work at high craft level individually. The result is a film that raised the entire genre when released and continues to reward repeat viewing seven decades later.
A 10+ is the only number that fits, and I’d give it without a second’s hesitation. The Id monster still disturbs me, the Krell machinery still makes me feel small, Robby is still funnier than most of the humans around him, and the Barrons’ score still sounds like it arrived from somewhere else. The Altaira material is weak and the 1956 surfaces show their age, but none of that touches the parts that made this film the template for so much of the science fiction I love.
