Interactive fiction, often abbreviated IF, describes software simulating environments in which players use text commands to control characters and influence the environment. Works in this form can be understood as literary narratives and as computer games. In common usage, the word refers to text adventures, a type of adventure game with text-based input and output. The term is sometimes used to encompass the entirety of the medium, but is also sometimes used to distinguish games produced by the interactive fiction community from those created by games companies. It can also be used to distinguish the more modern style of such works, focusing on narrative and not necessarily falling into the adventure game genre at all, from the more traditional focus on puzzles. More expansive definitions of interactive fiction may refer to all adventure games, including wholly graphical adventures such as Myst.

As a commercial product, interactive fiction reached its peak in popularity in the 1980s, as a dominant software product marketed for home computers. Because their text-only nature sidestepped the problem of writing for the widely divergent graphics architectures of the day, interactive fiction games were easily ported across all the popular platforms, even those such as CP/M not known for gaming or strong graphics capabilities. Today, interactive fiction no longer appears to be commercially viable, but a steady stream of new works is produced by an online interactive fiction community, using freely available development systems. Most of these games can be downloaded for free from the Interactive Fiction Archive (see external links).

The term "interactive fiction" is also occasionally used to refer to hypertext fiction, collaborative fiction, or even a participatory novel, according to the New York TimesFact: date=March 2008. It is also used to refer to literary works that are not read in a linear fashion, but rather the reader is given choices at different points in the text; the reader's choice determines the flow and outcome of the story. The most famous example of this form of interactive fiction is the Choose Your Own Adventure book series. For others, see gamebooks.

Medium

Text adventures are one of the oldest types of computer games and form a subset of the adventure genre. The player uses text input to control the game, and the game state is relayed to the player via text output.

Input is usually provided by the player in the form of simple sentences such as "get key" or "go east", which are interpreted by a parser. Parsers may vary in sophistication; the first text adventure parsers could only handle two-word sentences in the form of verb-noun pairs. Later parsers, such as those built on Infocom's ZIL (Zork Implementation Language), could understand complete sentences.DeMaria, Rusel and Wilson, Johnny L. (2002) High Score!: The Illustrated History of Electronic Games McGraw-Hill/Osborne, Berkeley, Calif., p. 52, ISBN 0-07-222428-2 Later parsers could handle increasing levels of complexity parsing sentences such as "open the red box with the green key then go north". This level of complexity is the standard for works of interactive fiction today.