Halo is a popular series of first-person shooter video games developed by Bungie Studios and published by Microsoft. Halo quickly became known as the first "killer app" for Microsoft's Xbox console, achieving both critical acclaim and financial success. The game was later ported to the PC and finally released for its originally intended platform, the Mac. A second game, Halo 2 was released in 2004, and the third game, Halo 3, was announced as available in 2007 for the Xbox 360, during Microsoft's press event at the E3 Expo in Los Angeles on May 9th, 2006. The Halo games have become well known for their impressive graphics, realistic physics, and engaging storyline; these are characteristics they share with previous Bungie works, including the Marathon series on the Mac. Further enriching the Halo universe are several novels, which provide insight into the background story, and a movie currently in pre-production.

Template:Spoiler Halo was the most popular application for the Xbox console up until the release of its more ambitious sequel, Halo 2. The series follows the events of the full-scale holy war between future humanity and a collective of alien races known as The Covenant. The player takes on the role of the Master Chief, a human supersoldier equipped with a technologically advanced battle armor, during his fights against the Covenant, through the discovery of the mysterious Halos and their deadly secrets.

The story of Halo: Combat Evolved deals with the adventures of the protagonist, referred to in the game only as "Master Chief" or, alternatively, Spartan-117. Stranded on a ring-shaped structure called "Halo" with the crew of the Pillar of Autumn, including the AI Cortana, the Chief fights against The Covenant, an alien alliance waging a holy war of sorts against humanity, while attempting to uncover the ring's terrible secrets.

Main article: Halo: Custom Edition

Halo: Custom Edition is a free stand-alone expansion for Halo: Combat Evolved (for the PC) that has the ability to load and play user-created content and maps. This version does not have the option to play in campaign mode. During an online match, players with the same user-created map can play together on it. Such maps include custom content such as vehicles, weapons, scenery, etc. More recent maps include recreations of Halo 2 maps.

Halo 2 was released for the Xbox on November 9, 2004, generating a $125 million dollar entertainment record on its premiere day. It was recently announced that a PC port for the Windows Vista operating system is currently in development by an internal team composed from both Microsoft Game Studios and Bungie Studios.

The sequel features new game mechanics such as dual wielding, new vehicles and weapons, better A.I., the ability to hijack vehicles, and Internet-based multiplayer via Xbox Live. Some easily seen changes between Halo 2 and its predecessor are in the weapons arsenal, which features a new battle rifle, a scopeless pistol, a submachine gun and the Covenant Carbine; also a new Covenant vehicle known as the Spectre has been included and previously seen vehicles such as the Warthog, Ghost, Banshee and Wraith have new features or weaponry. The game also touts an advanced graphics engine that utilizes normal mapping and bloom effects, helping to make it one of the best looking games on the Xbox. It also has Bungie.net integration and rankings and tracking of every online match, pushing the envelope of online console gaming further. Halo 2 also supports the same LAN and split-screen multiplayer found in Halo: Combat Evolved.

Although Halo 2 is much more ambitious than its predecessor, both through the scope of its campaign and the inclusion of new features, there is heated debate over whether the game is inferior compared to its predecessor, mostly from the viewpoint of competitive multiplayer gamers. Despite this controversy, Halo 2 continues to be one of the most-played titles on a Microsoft console, even continuing to be the most-played title on Xbox Live well after the release of the Xbox 360.

A trailer of Halo 3 was shown at Microsoft press conference at E3 2006. The trailer is now available online at most gaming sites including IGN.com, Gamespot.com, Bungie.net and is also accessible on Xbox Live Marketplace for free. The trailer is set on a ruined earth, and features the revelation of an installation which many fans understand to be the "Ark" mentioned at the end of Halo 2. It ends with the line Finish the fight 2007, finally giving a timeframe for the release of the game.

The trailer is rendered in real-time on the Xbox 360, using the current version of the Halo 3 game engine. The HDR lighting, self-shadowing, GPU-run particle system as well as other effects should make it into the final game intact. Halo 3 is planned to end the current Halo story arc, but no official word has been made by Bungie Studios as to whether it will end the Halo series.

Some fans believe Halo and Halo 2 were influenced by a number of other games and pop culture references, partially based on the game series own references to some of these pop culture icons. These include StarCraft, the Alien and Predator movies, the game Marathon (also created by Bungie, makers of Halo) series, Larry Niven's Known Space universe, and it borrowed heavily from the Ender's Game series, written by Orson Scott Card. No comment has been made about these possible influences by the developer and these ideas are only speculation.

A number of weapons and plot devices seem to borrow from ideas seen in the Marathon series of first-person shooters made by Bungie in the early to mid-1990s (see List of weapons in the Halo universe).

These include the concept of MJOLNIR "cyborgs", the supersoldier main character, the weapons, artificial intelligences, and even some of the alien creatures. Upon close inspection, crew members of the Pillar of the Autumn have the Marathon symbol on their uniforms, and the symbol is even embedded in the Halo logo itself. The Elites from Halo are somewhat similar (in their appearance, not their role) to Marathon's Pfhor. Hunters appear in both games filling the same roles. The Hunters from Halo, though much larger, also clearly share design elements with the Hunters from Marathon. A type of alien that was modeled for Halo 2 but later cut is nearly identical to the Drinniol from Marathon. Also, both games use uniform color to differentiate between different ranks of aliens (and crew members), with higher ranks being stronger and harder to kill. There are two multiplayer gaming options, a version of King of the Hill and a game called Oddball (called "Kill the Man with the Ball" in Marathon), which are present in Marathon's multiplayer mode.

These large similarities led to early speculation that Halo took place in the same universe as Marathon, only with different time frames; however, this was later proved highly unlikely. According to both the Halo video games and books, the events in Halo coincide with the events in Marathon. However, due to technology differences (the lack of transporter technology in Halo, for one), this is impossible. On Bungie's own Marathon page, there is a Q&A which states, "Is Marathon the prequel to Halo? [...] No, Marathon is a separate story, with wholly different characters, story and gameplay." [1].

However, some have even argued against this, citing Bungie's nearly irritating use of exact wording. The people who misbelieve it claim that the FAQ asks about a Prequel, which in literary terms, uses the same characters, setting, or even the same storyline. However, if Marathon and Halo were in the same Universe, just different timeframes, this could not, in fact, be a Prequel. Bungie may never tell the public however.

Some film parallels in the games have been pointed out by various people. For instance, the active camouflage power-up is very similar to the type of camouflage used by the alien Yautja in the Predator film series. There are notices near the Pillar of Autumn's bridge looking for a cat named Jonesy (the name of Sigourney Weaver's cat in the Alien film series). Elites' mouth parts are similar to the Predators' with bodies very similar to the Xenomorphs. The Flood Spores share a similar purpose with the Face Huggers in the Alien film series. Bill Paxton's character from the movie (Pvt. Hudson) says "I've got a bad feeling about this, man" and is answered with "Man, you always got a bad feeling!", a quote which is used in the cut-sequence right before Master Chief has his first encounter with the Flood. Also, there are numerous similarities between the marines of Halo and those of Aliens. The colonial marines' dropship resembles a Pelican and the Pelican pilot Foe Hammer is based on the dropship pilot from Aliens. Finally, Halo's Sergeant Johnson is very strongly based on Aliens' Sergeant Apone - both are very enthusiastic, black, cigar-smoking squad leaders. Both characters even use the line "They're not paying us by the hour, marines!" Enemies will sometimes use the line "its only a flesh wound", from Monty Python and the Holy Grail.

Ringworld is a megastructure 93 million miles in radius that resembles the Halo installations, albeit on an enormously larger scale. This idea has been copied numerous times in science fiction, although normally on a larger scale than in Halo. In both Halo and Known Space, humans develop space travel on their own and later encounter a hostile and technologically superior alien civilization. In one of Larry Niven's early Known Space novels, World of Ptavvs, it details an alien race, known as the Thrintun, and how they ruled a massive empire 2 billion years before humanity, through advanced mind control. At one point, the Thrintun's most advanced slave race eventually instigated a massive rebellion, using much of their own technology, which was developed for their masters, against them. The Thrintun, fearing extinction and intense paranoia, used an amplification device that targeted the minds of all sentient lifeforms and simply told them to "die". The wave from this device spread across the entire galaxy, killing all sentient life, including the Thrintun themselves. In Halo, the Forerunners used the Halos to extinguish all intelligent life in the galaxy, in order to prevent The Flood from escaping the Halo installations.

Halo took names from world history and mythology to aptly name objects and important characters in the Halo universe. Some of these names include:

• Cortana, derived from a sword used by Edward the Confessor.
• Beowulf, a hero in the Anglo-Saxon poem "Beowulf".
• Tartarus, a deity and a place in the Greek mythological underworld.
• MJOLNIR, Thor's Hammer.
• SPARTAN, the Ancient Greek polis of renowned martial prowess, Sparta.

Alternatively, it is possible (or even likely) that Halo was inspired by the Orbitals featuring in The Culture novels by Iain M. Banks, as they are ring-shaped megastructures that orbit stars or gas giants, rather than rotate around them. These smaller structures have the advantage of not needing additional machinery to generate a day/night cycle. Furthering this theory is the fact that the Covenant resemble in no small measure the Idiran race, religious zealots bent on eradicating The Culture, which they regard as heretical or that the Forerunner robot 343 Guilty Spark resembles a Culture drone. The titles of the ships, and the names of the levels are extremely similar to the naming method Banks uses in his novels; whimsical names in Marathon and Halo are common, "Guilty Spark", "Never Burn Money" etc. are similar to the Culture ship's names, "Nervous Energy", "Sleeper Service", "Grey Area"

Halo seems to be inspired by a number of other science fiction books. The Drones that appear in Halo 2 resemble the "Buggers" from Ender's Game, as in the third level they are referred to by Sgt. Johnson as "Buggers, heading over the rooftops!" There are numerous other possible references to Ender's Game, such as the Spartan program, which closely mirrors the super soldier program from the novel. Starhammer, written by Christopher Rowley, details the story of a genetically altered man named Jon 6725416 who escapes slavery by a race of technologically advanced overlords threatening to destroy humanity, and finds an ancient weapon that was created by an ancient race to destroy a parasitic alien life form called the Vang that may have been a partial basis for the Flood. 343 Guilty Spark is also very similar to Durandal, an AI from Bungie's earlier Marathon Series, as the two seem to share a similar manner of speech. Both Durandal and 343 Guilty Spark also "control" the player during gameplay, directing the player where to go an opening certain doors to aid progression. In the book Starship Troopers, the Mobile Infantry are equipped with powered armor and are launched down to the surface of a planet in pods, not unlike the Spartans and ODSTs of Halo. The Halo series also shares similarities with Blizzard's StarCraft series, especially the "Three Races" concept: "Terran, Protoss, Zerg" is now "Human, Covenant, Flood". This can be seen because the Protoss and Covenant are both very technogically advanced and religious. The Flood and Zerg are also both parasitic organisms.

There are subtle references to the Christian Bible in the Halo series. For example, the story of Noah could be a possible influence for The Flood, as The Ark could be interpreted as a reference to Noah's Ark (saving its occupants from The Flood). Interpreted another way, the Ark of the Covenant symbolizes the destructive power of the Ark, which can activate all of the Halos. Another reference would be Master Chief's real name being John, and designation number 117, possibly relating to John 1:17 in the Bible: "Because while the law was given through Moses, grace and truth came through Jesus Christ." Other permutations of Biblical verses derived from John's name and designation are also possible.

Halo uses a number of common plot devices, although often they are not immediately apparent.

• The main character has few lines and is accompanied by a technically adept sidekick.
• People searching for valuable objects instead release something evil.
• The main character is saved by someone who later betrays him.
• The only way to defeat an enemy is to blow up the world (or Halo, in this case). This plot device also drives the plot involving the Flood and the true purpose of the ring-worlds.

Three novels based on the Halo series have been released so far. The first one in the trilogy is Halo: The Fall of Reach; written by Eric Nylund, it acts as an immediate prequel to the events portrayed in Halo: Combat Evolved. The second book, Halo: The Flood, is a novelization of the first game and was written by William C. Dietz. Halo: First Strike is the third novel to be released and was also written by Eric Nylund. The book's story starts immediately where Halo: Combat Evolved left off and acts as prequel to Halo 2. Other Halo novels are currently rumored to be in development. Also, the Halo series is being translated into a graphic novel as well: the Halo Graphic Novel will be released in July, 2006.

A film adaptation of the game, being produced by Peter Jackson and wife Fran Walsh as executive producers, is expected to be released in 2008 (see Gamespot.com press release).

A large body of fan fiction based on the Halo series has been written, covering both the past and future of the setting. The sites bungie.net and halo.bungie.org both host collections of Halo fan fiction. Indeed, there are several works of fan fiction that run to the length of a novel or more, and are well-known among the Halo community. Additionally, fanfiction.net hosts a selection of over 1,000 Halo-inspired pieces.

The Haunted Apiary (aka I Love Bees) was an alternate reality game used to promote the release of Halo 2. The game was centered on a website at ilovebees.com, and was created by 4orty2wo Entertainment, commissioned by Microsoft and endorsed by Bungie. The URL was discovered when it was briefly flashed in an official Halo 2 trailer.

Red vs Blue: The Blood Gulch Chronicles, made by Rooster Teeth Productions, is a machinima series that parodies the Halo universe. Virtually all of the footage of the series is taken from Halo and Halo 2 gameplay. Set mostly outside Halo canon, the series chronicles the story of two opposing teams fighting—in Blood Gulch, a desolate box canyon "in the middle of nowhere"—a human civil war that supposedly ensues between the events of Halo: Combat Evolved and Halo 2. An absurdist parody of Halo itself, military life in general, and other science fiction films, Red vs Blue is based largely on comedy and can be found at RedvsBlue.com.

Other machinima series—ranging from Fire Team Charlie, another comedy, to The Codex, a space opera more closely tied to Halo canon — have also been created. Even a parody of the parody can be found with Purple And Pink, a Christian spoof of Red vs Blue that aimed to both entertain as well as enlighten the gaming youth with such topics as friendship, discipline and respect.

Three soundtracks, all composed by Martin O'Donnell, have been released based on the Halo game series:

• Halo Original Soundtrack

• Halo 2, Vol. 1: Original Soundtrack

• Halo 2, Vol. 2: Original Soundtrack

Recently, the creators of Halo were listed in Time's 100 most influential figures of the past year. This is due to the reason that Halo manages to appeal to both casual and hard core gamers, and broke sales records, making gaming more mainstream entertainment.

• Halo Zero, a fan-made 2D sidescroller set in the Halo universe.

• Halo: Spartan was a supposedly cancelled Gizmondo game that was in pre-production, but was only so to generate stock numbers. It was said that it was going to be controlled with the mounted-camera on the Gizmondo for superior FPS controls.[2]

• Bungie Studios
• Halo Community
• MobyGames' entry for the Halo Series
• Halo Pro - Large online movie resource
• HBO, a large web resource for Halo-related topics
• Halo & Bungie News
• Halo 3 Blog
• Halo 3 Multiplayer
• I Love Bees - See Haunted Apiary.
• HaloWiki