IMAGINE THAT IF every time a film was released, everyone who saw it was welcome to use any aspect of it as raw material for his or her own movie: all the characters, all the settings, all the costumes, props, and music. So you'd have Casablanca told from Sam's POV, or from Major Strasser's POV. Or maybe the Nazis would win; or Ilsa would betray Rick and turn him in. Or maybe someone would decide that the whole thing would be better if it were set in a high school in Hawaii in the year 2123. All those people would have access to the same tools -- and more importantly, the same distribution channels -- as the original creators; the only limits to what they could do would be imposed by the tools themselves, their skill in using them, and the amount of time they had to put into their various visions.

That's pretty much what's going on in the world of mods and computer gaming at the moment.  Whether it's been hacked or backwards-engineered or released by the company, a game's source code quickly becomes the raw material for a new generation of game worlds -- for stories and contests unlike anything the original creators might have imagined.  The truth is, if a video game develops any sort of following, the end is just the beginning. The final battle with the final boss is merely the starting point for a whole new set of killing floors, for new fields of play. And their names are legion: Counter-Strike; Hong Kong Blood Opera; Rocket Crowbar; Unloaded; Lithium; Jailbreak; Team Fortress; Benny's Dead; Snarkwars.

ID SOFTWARE is generally credited with being the founders of the mod movement ... almost: When they created Doom, they built it so it would be easy to hack, thus encouraging amateur programmers to come up with their own spin on the ground-breaking shooter. This had the dual effect of dramatically increasing Doom's longevity (people played variations of the game long after they had finished the original) and dramatically increasing sales (people had a reason to buy the game long after it would otherwise have been considered unthinkably ancient).  Since then, more and more games have been released along with their source code; Unreal was one of the first to be released with the same tool suite the developers used to make the original game.

A quick look around the Net reveals the current size of the mod community and the scope of their ambitions. Modcentral lists 105 mods for Half-Life alone, 75 for Quake 3; BotEpidemic, a site devoted exclusively to 'bots, or artificial opponents and/or helpers for games, has 34 varieties of 'bots for the venerable Quake I available for download, each with varying degrees of (artificial) intelligence. Most of the mods are for multiplayer death matches, and so there is a certain similarity that they all share. But you can find variations ranging from Wild West recreations complete with long six-shooter barrels to sight down, to simple weapons tweaks, to blood soaked versions of pong and volleyball. The aforementioned Blood Opera aims to recreate the experience of a shoot-out in a John Woo film, complete with blazing double Glocks and a twisting, somersaulting POV; you rack up style points for your kills as well as for simple body-counts. Counter-Strike has succeeded in changing the rules of the games business forever: Built and distributed for free, the Half-Life-based game has become the single most popular shooter online. According to various reports, at any given moment, more people are blazing away on a Counter-Strike battlefield than are playing all other action games combined.

All of which is why, in this special issue, FEED takes a closer look at mods and the fast-growing mod community. In this issue's main feature, we asked a group of writers and game-players to compose tributes to their favorite mods: Carl Steadman talks about his favorite Quake 3 and Unreal Tournament mods, both radical re-imaginings that transform the games from a 3-D to a 2-D experience. Justin Hall talks about the most successful mod in game history, the online-only experience called Counter-Strike.  Wagner James Au checks in on the still unfolding and constantly expanding story of Garrett, star of Looking Glass Studio creations Thief and Thief II, and the upcoming Ion Storm-built Thief III. Steven Johnson looks at the notorious Guinea Pig mod for The Sims. Francis Hwang gives a rundown on the shadowy world of cheats and hacks. A little later in the week, on Thursday, Steven Johnson presents a new "Interface" column that talks about the much-hyped new game Oni, and includes an exclusive interview with Oni's lead designer.  And finally, on Friday, we have an interview with Ion Storm's star game designer Warren Spector, who talks to us about mods, narrative, and eagerly awaited sequels Thief III and Deus Ex 2.

We've always imagined this issue as being one that you could play as much as read, so we've included links to all the relevant downloads in the margins of the issue. As always, we want to hear your experiences -- your favorite mod or your thoughts on gaming culture in general -- in the Loop at Plastic.

Are you mod or a rocker? Share your thoughts in the FEED threads at Plastic...