Eamon, sometimes known as The Wonderful World of Eamon, is a game creation system and a role-playing adventure game series created by Donald Brown and released for the Apple II in 1980. The game is a text adventure similar to other early titles like Adventure (1976) or Zork (1980) and to later text-based multi-user dungeons (MUDs), though with many role-playing elements not available in other interactive fiction. Eamon software is non-commercial and is freely available in the public domain.

Eamon casts the player in the role of a free-wheeling fantasy adventurer who undertakes dangerous quests against numerous enemies to earn riches and experience. Home base is the Guild of Free Adventurers, an association of heroes on the mystical world of Eamon, a vaguely Medieval place awash in magic and populated with strange creatures. Most adventures take place in the dungeons, castles and forests of Eamon, though some occur on other worlds or in different eras. Eamon creator Donald Brown described Eamon as "a world at the center of another galaxy—instead of revolving around any star, all of the stars revolve around it! Those huge bodies exert strange effects on the world of Eamon, bending light, gravity, time, even the laws of nature themselves!"

Though influenced by such fantasy environments as Dungeons & Dragons and The Lord of the Rings, Eamon generally avoids stories, situations or other game elements that are particularly serious or complex, instead seeking to create an engaging, genial mood through quick play and in-jokes. Individual adventures, created by a wide range of authors, vary from the artful to the campy.

Robert Clardy's Odyssey: The Compleat Apventure displays the same dragon artwork on its title screen as Eamon.

Brown encouraged players to modify and add to Eamon, and published technical information on the game to assist them. Eamon is notable for being one of the first adventure games designed to be modular, with expansion packs written by users forming an integral part of the game experience. A master disk called the "Main Hall" is used to manage player characters and to facilitate their transfer between individual adventures. The character retains his or her attributes and statistics from adventure to adventure, as well as up to four weapons.

The game's interface is similar to that of most other text adventures — the game presents the player with descriptions of the character's surroundings, including events, artifacts, monsters and exits, then prompts the player to enter a command. These commands include such things as moving in certain directions (NORTH, EAST, UP, etc.), readying weapons, attacking, getting or dropping items, interacting with characters, casting magical spells or checking inventory.^{[citation needed]}

All player characters in Eamon possess a name, plus the three physical attributes of hardiness, agility and charisma in varying quantities. Hardiness affects how much a player can carry and how much damage he can both inflict and withstand. A strength of 12, for instance, allows the player to absorb 12 points of damage and lift 120 gronds (a fictional unit of weight used in the game). Agility influences the player's success using certain weapons and avoiding attacks, while charisma determines his ability to make friends and influences the prices he pays for supplies. Common attribute values for player characters are generally between 10 and 20.

Players also have varying abilities with five classes of weapons — axe, bow, club, spear or sword — expressed as a percentage. Scoring a hit in battle may increase the skill in the appropriate weapon class. An additional ability, "armor expertise", determines the extent to which the player's armor affects his chance to score a hit. The greater the expertise, the less the armor encumbers the player in combat. Players may wear leather, chain or plate armor, and can supplement this with a shield.