0451

The code 0451 unlocks the first locked door in Deus Ex games. The number also appears in various other manners in the Deus Ex series.

Origin
The number first appeared in the original System Shock (as ) and its sequel System Shock 2 (as  ). Both games were developed by. The number was initially thought to be a reference to 's dystopian novel , in which it represents "the temperature at which book-paper catches fire and burns". However, in 2015, Warren Spector revealed that 0451 was actually just the door code to access the Looking Glass Studios offices in Cambridge, Massachusetts:

As to the purported reference to Bradbury's Fahrenheit 451, Spector subsequently stated that "the Bradbury reference is just a nice bonus." Gaming media site IGN suggested that the door code itself was a reference to Fahrenheit 451. However, this notion has not been confirmed by any known developer account or direct source.

Regardless of whether Fahrenheit 451 was or was not the original basis, the code was nonetheless associated with Fahrenheit 451 by Looking Glass Studios employees during the development of System Shock. Former Looking Glass Studios employee Tim Stellmach stated the following in 2015: "That 0451 code has become kind of a signature that developers use to align themselves with Looking Glass. It is itself, of course, a nod to Ray Bradbury’s Fahrenheit 451, as dystopian science fiction was naturally on everybody’s mind during System Shock development." Consistent with this account, in 2001, Harvey Smith described the code in Deus Ex as "an allusion to System Shock's allusion to Fahrenheit 451."

Similarly, Eidos Montréal, in addition to using the number 451 as the first door code in its Deus Ex games, has also associated the number with Fahrenheit 451 in certain contexts. Direct references to Bradbury's Fahrenheit 451 have appeared alongside mentions of "451" in Deus Ex games developed by Eidos Montréal.

The code 0451 has since appeared in numerous other games developed by former Looking Glass employees, including BioShock, Dishonored, Prey, The Last of Us Part 2 and others.

In Deus Ex games and books

 * In Deus Ex, the code 0451 opens the comm van near the UNATCO Headquarters.
 * Deus Ex: Invisible War does not have enterable codes, but the protagonist Alex D starts in the dorm room 451 of the Seattle Tarsus Academy.
 * In Deus Ex: Human Revolution, the code 0451 opens the elevator in David Sarif's office. It is used again as the first code in The Missing Link DLC.
 * Also, a direct reference to the Fahrenheit 451 and its author Ray Bradbury is made through an announcer in the Detroit Police Station, asking for "detective Bradbury in office 451".
 * In Deus Ex: The Fall, the code 0451 opens the door to Mikhail Kontarsky's hideout in Hotel Novoe Rostov.
 * In the book Deus Ex: Black Light, Adam Jensen wakes up from coma in Facility 451 in Alaska.
 * In Deus Ex: Mankind Divided, the code 0451 unlocks the first door encountered during the Dubai mission. A Heated Combination achievement is awarded for entering the code instead of hacking the lock.
 * 0451 is the number of the United Nations resolution that ratified the creation of Task Force 29.
 * Another reference to 451 is made in a Picus TV news report that mentions a Cista Airlines 451 plane crash.
 * A direct reference to Fahrenheit 451 is made in an e-mail found in the Time Machine. The e-mail is from R. Brad Burrie and refers to a shipment of rare books on train F451.
 * In Deus Ex GO, it is the code needed to access Novak's secret lab.

In real life

 * Jonathan Jacques-Belletête, art director of Deus Ex: Human Revolution and Deus Ex: Mankind Divided once had a flight number 0451. He wrote about that on Twitter.