Campaign

A "campaign" (or "chapter" - see notes) is a major component of the Guild Wars game series. Each of the first three campaigns is stand-alone game, and does not require any previous campaigns of Guild Wars to play. These campaigns and must be purchased individually as a full game, although they can be "linked" to a single account, allowing characters on that account to travel between the campaigns. The fourth Guild Wars release, Eye of the North, is an expansion rather than a standalone game, meaning only players who already own one of the original three campaigns are able to play it.

Each campaign adds large amounts of new content, but also includes common core content present in all campaigns.

ArenaNet has stated that they plan to release two campaigns per year, and each campaign will have a development time of about 1 year.

During installation the player may choose whether he or she wants to create a new account for each campaign, or to link all of the campaigns to one account, allowing characters to travel across all campaigns activated on the account.

Campaigns

 * Campaign One: The original Guild Wars, a.k.a. Guild Wars Prophecies, released April 28, 2005.
 * Campaign Two: Guild Wars Factions, released April 28th, 2006.
 * Campaign Three: Guild Wars Nightfall, released October 27th, 2006.

In addition to the above, there exists Core content shared by all campaigns. Locations for access to some core content was relocated or introduced into the game in the January 19th, 2006 major update in order to make it available to all campaigns.

Expansions

 * Eye of the North, released August 31st, 2007.
 * Bonus Mission Pack released November 29, 2007.

Major updates
A major update introduces a new explorable areas, towns and/or a number of new quests to the existing game, rejuvenating interest in the game. Major updates are different from chapters in that they are free and their content is incorporated into the existing world map. While both types of releases add more locations, items and quests, chapters also add new professions, skills, and a new epic quest spanning previously unmapped territories.

Major updates since the initial release
These updates were official referred to as major as part of their release:
 * September 7th, 2005: Introduced Sorrow's Furnace to Guild Wars Prophecies, including two new explorable areas, several quests, and new items (including unique/green items dropped by the numerous Furnace bosses).
 * January 19th, 2006: Introduced the Tomb of the Primeval Kings, including a new explorable area and moved most PvP content to The Battle Isles.
 * December 1st, 2006: The Domain of Anguish was added to Guild Wars Nightfall.