If you take the first letters of the main characters' names - Dom, Robert, Eames, Arthur, Mal and Saito - they spell "Dreams". If you add Peter, Ariadne and Yusuf, the whole makes "Dreams Pay", which is what they do for a mind thief.
"Yusuf" is the Arabic form of "Joseph", the Biblical figure from Genesis 37-50, who had the gift of interpreting dreams. He was sold out by his brothers to slavery. Through his gift of dream interpretation he helped Pharaoh to prepare for the disaster of the "seven lean years" and was rewarded as a result. The same story is also told in the Koran.
In an interview with 'Entertainment Weekly', Christopher Nolan explained that he based roles of the Inception team similar to roles that are used in filmmaking - Cobb is the director, Arthur is the producer, Ariadne is the production designer, Eames is the actor, Saito is the studio, and Fischer is the audience. "In trying to write a team-based creative process, I wrote the one I know," said Nolan.
Christopher Nolan first pitched the film to Warner Bros. after the completion of his third feature, Insomnia (2002), and was met with approval from the studio. However, it was not yet written at the time, and Nolan determined that rather than writing it as an assignment, it would be more suitable to his working style if he wrote it as a spec script and then presented it to the studio whenever it was completed. So he went off to write it, thinking it would take "a couple of months", but it ultimately took nearly eight years.
The Édith Piaf song "Non, je ne regrette rien" is used as a plot device. Marion Cotillard played Piaf in La Vie en Rose (2007). Christopher Nolan has stated that this is "pure coincidence". After Cotillard was cast Nolan intended to change the song to eliminate speculation on the subject, but composer Hans Zimmer persuaded him to keep it.
Marion Cotillard's character is called 'Mal', short for name 'Malorie', a name derived from French word 'malheur', meaning misfortune or unhappiness. The shorter version 'mal' means wrong/bad or evil (when a noun) in French, as well as some other Latin-based languages.
Dom Cobb's main objective is to get Home. His name, Dom, literally means 'home' in most Slavic languages. The root word "*dom" comes from the Latin word "Domus". Words like 'Domesticated' and 'Domicile' all share the same "*dom" root.
The slow, gloomy, blaring trombones in the main theme of the film score are actually based on an extremely slowed down version of the fast, high pitched trumpets in the beginning of the Édith Piaf song "Non, je ne regrette rien," which is used as a plot device in the film. Furthermore, when music is heard by someone who is currently within a dream, the music is perceived as slowed down. Thus, the main theme of the film score is almost exactly what the beginning of "Non, je ne regrette rien" would sound like to a dreamer. This thematic device is brought to its logical conclusion when the song plays at the end of the credits, signaling that the audience is about to 'wake up' from the film.
A direct translation of the lyrics for the song "Non, je ne regrette rien" as performed by Édith Piaf is: "I regret nothing/no, I have no regrets/I regret neither the good things that were done to me nor the bad things/They are all the same to me/...The past is payed, swept away, forgotten/I don't care of the past anymore/I set my memories on fire/My agonies, and my pleasures/I don't need them any more/Swept away in the agonies of love/Swept away forever, I'm restarting with nothing..." Christopher Nolan has made a point of saying that he chose the song specifically for the movie, which is heavily concerned with the effect of memories on the psyche, and specifically the disastrous effect that not letting go of memories of love-gone-wrong can have on the subconscious--exactly what the song discusses. Also of note: in the original French, "I regret neither the good things done to me nor the bad things" is "Ni le bien qu'on m'a fait ni le mal," and since Cobb's wife is named Mal, that gives the line a double meaning.
During production, details of the film's plot were kept secret. Christopher Nolan, who wrote the script, cryptically described it as a contemporary sci-fi action thriller "set within the architecture of the mind."
Just as Cillian Murphy's character was named Robert Fischer as a tribute to champion chess player Bobby Fischer, his father's (Pete Postlethwaite) character is named Maurice Fischer as an homage to artist M.C. Escher (full name Maurits Cornelis Escher), whose art was clearly an inspiration for many of the special effects in the film.
Ariadne, in Greek mythology, was the daughter of King Minos of Crete and his queen, Pasiphaë. She aided Theseus in overcoming the Minotaur by giving him a ball of red fleece thread that she was spinning, so that he could find his way out of the Minotaur's labyrinth. The name is also a reference to Hugo von Hofmannsthal's setting of the myth for Richard Strauss's opera The Metropolitan Opera Presents: Ariadne auf Naxos (1988). The opera is a play within a play, just as the movie is a dream within a dream.
When explaining why he thinks implanting an idea is not possible, Arthur says "don't think about elephants" to actually make Saito think of them and thus "insert" an idea into his mind. The line is a reference to the title of a famous cognitive semantics book, 'Don't Think of an Elephant' by George Lakoff. The book describes conceptual framing, the use of certain words to literally insert certain ideas about a subject into the listener's mind in a surreptitious way, e.g. implanting the idea that taxes are a bad thing by using the phrase "tax relief."
The exterior of Fischer's snow fortress is based on, and actually contains some elements of, the Geisel Library at the University of California, San Diego, designed by famed futurist architect William L. Pereira.
The barrel chairs in Saito's dining room were designed by Frank Lloyd Wright in 1937 for Wingspread, the Herbert Johnson house in Wisconsin. Saito sits at the head of the table in a copy of the Willow Chair designed by Charles Rennie Mackintosh in 1903. This further plays on the Architect theme that is prevalent throughout the movie.
The role of Saito was written exclusively for Ken Watanabe because Christopher Nolan felt that although he had appeared in Batman Begins (2005), he did not have much screen time, and should therefore be given a more prominent supporting role.
Early in the film, during Mal and Cobb's conversation in a room within Saito's estate, Mal comments on a painting in the background. Cobb replies stating that Saito "is partial to postwar British painters". This is referring to the artist, Francis Bacon. The painting, "Study for Head of George Dyer", is of his late lover, whom he painted long after Dyer's death to perpetuate his memory.
One of the reasons why Christopher Nolan cast Tom Hardy as Eames was because of his performance in the film RocknRolla (2008). Hardy stated that he thought he was cast because of his role in Bronson (2008). He arrived on set only to learn that Nolan has never even seen Bronson.
According to Cinematographer Wally Pfister, Warner Brothers executives approached Christopher Nolan about making the film in 3D, but he refused the idea, claiming "it will distract the storytelling experience of Inception".
A series of numbers keeps appearing: the number that Fischer gives Cobb/Arthur is 528491, The two hotel rooms used are rooms 528 and 491, the number that Eames (as a woman) gives to Fischer is 528-491, the combination to the strongroom starts with 52, and the combination to the safe is 528-491. This is all to reinforce the importance of the number throughout the film.
There are 399 questions asked in the film, including "tag questions" (i.e. - "Subconscious is motivated by emotion, right?"). Cobb leads all characters with 113, followed by Ariadne (93), then Arthur (44).
Christopher Nolan's first film since his feature debut, Following (1998), that is a completely original work. All of his films between them are either remakes or based on comics, novels or short stories.
The character Cobb is an architect in this movie. The actor Alex Haw, who played another character also named Cobb in Christopher Nolan 's earlier movie Following (1998), is actually an architect in real life.
The "Penrose stairs" (with a woman perpetually picking up papers) that Arthur shows Ariadne is a reference to a lithograph print by the Dutch graphic artist M.C. Escher. The print is usually called "Ascending and Descending" or "The Infinite Staircase", and was first printed in March 1960; Escher is well-known for his drawings exploring optical illusions and real architectural, mathematical, and philosophical principles rendered in fantastical ways.
The IMAX 65mm format was earlier considered, as used in The Dark Knight (2008), but it was eventually ruled out due to extensive hand-held camera usage throughout the shoot. Due to its weight, it cannot be operated hand-held.
Mal's totem, a spinning top, is (probably) a reference to the Clifford D. Simak's story 'Ring Around the Sun' where the spinning top is used as a way to skip from one parallel Earth to another (by way of helping characters to concentrate).
In the scene where we first see Cobb and Miles, Cobb's character mentions "Extradition between France and the United States is a bureaucratic nightmare." In Catch Me If You Can (2002), Leonardo DiCaprio plays a character who is arrested in France and extradited to the United States.
Ariadne makes her first appearance where she is called upon to create mazes. She is named for a character in Greek mythology who helped Theseus find his way out of the Labyrinth after killing the Minotaur.
Lukas Haas plays The Architect, the member of the team who designs the dreamscape i.e. the world of the dream. In the 2002 TV adaptation of Ursula K. Le Guin novel "Lathe of Heaven" he plays George Orr - a man whose dreams change reality. In the novel George Orr is a draftsman.
One of Japan's famous "Bullet Trains" is seen early in the movie. This is a 700 Series Shinkansen on the Tokaido line from Tokyo to Osaka. Its distinctive "duck bill" nose and tail design helps to reduce the air piston effect as the train enters tunnels at speed.
Although Tom Berenger appears in several scenes, the only scene where his character is "real" (That is, when he's not a projection of someone else's subconscious or being impersonated by Eames) is his first appearance in Maurice Fischer's office.