“It is pitch black. You are likely to be eaten by a grue.” Dave Lebling wrote the monster behind that warning, and a good deal more of Zork: the command parser the game grew from, its fighting, its thief, and the boundary that cut a one-megabyte mainframe game down to the first home-computer Zork. He was one of the ten founders of Infocom, and over the next decade he wrote some of its most varied games, from hard science fiction to a murder at a costume ball, a horror story set in a thinly disguised MIT, and an adaptation of James Clavell’s Shogun.
Fast facts
- Full name: P. David Lebling.
- Education: MIT, where he studied political science.
- Before Infocom: the Dynamic Modelling Group at MIT’s Laboratory for Computer Science.
- Infocom: a founder in 1979; wrote or co-wrote nine of its games.
- After Infocom: software for Avid Technology and other companies outside the games industry.
- Honours: the Academy of Interactive Arts & Sciences’ Pioneer Award, with Marc Blank, in 2013.
MIT and the Dynamic Modelling Group
Lebling was not studying computing. Retro Gamer’s history of Infocom says he was taking a degree in political science, as Marc Blank was training to be a doctor, when both belonged to the Dynamic Modelling Group at MIT’s Laboratory for Computer Science. Lebling told Zzap!64 in 1986 that for about ten years before Infocom took off the group worked on “things which were artificial intelligence related”. It also played games. Your Computer, writing Infocom’s history in 1987, described a Dynamic Modelling Group game in which several players wandered a maze shooting each other, each screen showing that player’s own view of the maze, and named Lebling as one of its chief developers. The Academy of Interactive Arts & Sciences credits him as a co-author of this Maze, which it calls the first first-person shooter played over the ARPANET.
Zork
When Adventure reached MIT in 1977, “we were really quite excited by it”, Lebling told Zzap!64, “but at the same time, we thought it had some limitations and decided to write a similar sort of game but better! So we did.” He had already written a command parser in MDL, the laboratory’s LISP-like language. With it he and Blank and Tim Anderson made a tiny test game; in Lebling’s recollection, given to PC Player in 1999, it had about half a dozen rooms and “pretty silly” puzzles. Then he went on holiday. When he came back, Anderson, Blank and Bruce Daniels had built a large part of Zork.
The four kept adding to it for two more years. When players complained that wandering in the dark ought to be dangerous, Lebling invented the grue. He gave fights wounds and weapons of different strengths, and gave the thief his stiletto. Players shaped the game too. Lebling told PC Player about the jewel-encrusted egg with a golden clockwork canary inside. One tester, looking at the new treasure, guessed that winding it up would make it sing and attract a real songbird that would give him a treasure. The game did no such thing, but the authors liked the idea so much that they added it, and the next day the tester tried it and it worked exactly as he had predicted.
Infocom
Infocom was founded on 22 June 1979 by ten members of the laboratory, Lebling among them. “We actually founded the company before we knew what we were going to do with it,” he told Zzap!64. Retro Gamer reports that Anderson and Lebling suggested selling Zork, which was already written and tested, and that Lebling sat on the first board of directors until November 1979.
The mainframe game would not fit a home computer with 32K. Lebling looked at his map of the Great Underground Empire and drew a boundary round about 100 locations, the house above ground and the area round the Round Room, and the rest was kept for sequels. In December 1980 he explained the result to BYTE’s readers, in an article on Zork and “computerized fantasy simulations” that described the parser, the virtual machine behind it and what the authors had learned. Zork I came out that year, credited to Lebling and Blank, and Zork II in 1981. Lebling said he worked “a little bit” on Zork III.
At Infocom he became known for his prose. Computer Gaming World wrote in 1985 that Lebling “has always described himself as the Master of the Purple Prose”, and that a player of his new game could “close their eyes and feel one of Dave’s rooms”. Commodore Magazine, visiting Infocom in 1988, found that he started a game by drawing its geography and then filling it with objects and characters, where Steve Meretzky started with the story. Lebling explained the company’s approach to testing: “We don’t like nothing to happen in response to the player’s command if we can help it.”
His games
| Game | Year | Notes |
|---|---|---|
| Zork I | 1980 | With Marc Blank |
| Zork II | 1981 | With Marc Blank |
| Starcross | 1982 | Hard science fiction |
| Zork III | 1982 | With Marc Blank; Lebling said he worked on it “a little bit” |
| Enchanter | 1983 | With Marc Blank; first of a trilogy about magic |
| Suspect | 1984 | A murder mystery |
| Spellbreaker | 1985 | Last of the Enchanter trilogy |
| The Lurking Horror | 1987 | Horror on a college campus |
| James Clavell’s Shogun | 1989 | Adapted from the novel, with pictures |
Starcross. Announced for late 1982, this was Lebling’s first game after the first two Zorks. He told Zzap!64 that it was a homage to Arthur C. Clarke’s Rendezvous with Rama and to Larry Niven, whose “stepping discs” became the coloured discs used in many of its puzzles. It came in a box shaped like a flying saucer, which ANALOG Computing complained could not be stacked or shelved. Many players found it Infocom’s hardest game, and Steve Meretzky later named it his favourite Infocom game.
Enchanter. Written with Blank, it gave the Zork world a system of spells. Lebling said he had thought during the Zork years that magic “would make an interesting addition to the games”, and that Ursula K. Le Guin’s Earthsea books inspired it. Meretzky wrote the second part, Sorcerer, and Lebling finished the trilogy with Spellbreaker, in which the magic is failing and the player, a powerful enchanter, has to find out why. COMPUTE!’s Gazette warned that it was an expert-level game, tougher than the first two, and called it Lebling’s “most complex and mature work of interactive fiction”. Lebling’s regret, he said, was the one every designer had: “you always wish there had been that extra 5K or 10K.”
Suspect. The player is a newspaper reporter at a society costume ball, dressed as the cowboy Roy Rogers, whose own lariat is used to murder the hostess. Lebling described it as combining “the rich texture of The Witness with the complicated plot structure that distinguishes Infocom mysteries”. ANALOG Computing thought it “probably Infocom’s most complex and truly ‘interactive’ adventure thus far”, with a whole cast to question. It was also, Lebling said in 1986, the hardest game he had written, and he vowed not to write another mystery until Infocom had a better parser.
The Lurking Horror. Computer Gaming World called it “Lebling’s paean to his M.I.T. days”: a student on a snowbound Massachusetts campus with a 20-page essay to finish discovers something horrible in the tunnels. The box held a plastic insect. Lebling told Commodore Magazine about a peach tree on a roof. He had meant to build a puzzle round it, but instead covered it in slime so that nobody could climb it: “I wanted to keep people from climbing the peach tree”.
Shogun. Infocom announced its licensed game of James Clavell’s novel in 1988, with Lebling as designer. Computer Gaming World’s reviewer reported that Lebling worked directly with Clavell, and that the player was the English pilot Blackthorne, starting at the ship’s wheel in a storm off Japan. The pictures imitated 16th-century Japanese art. The reviewer found it too quick to kill the player for a wrong guess. It reached the shops in 1989, after Activision had moved Infocom’s development to California; by then, Computer Gaming World wrote later, Infocom “was only a label”.
After Infocom
When Infocom’s Cambridge studio closed in 1989, Lebling chose to stay in Massachusetts. In 1999 he told PC Player he was working for Avid Technology, which made video editing and television studio software, and that his latest project was AvidNews, a newsroom system used by broadcasters including Germany’s ARD and ZDF. He thought hobbyists would always write text adventures, and pointed readers to the Usenet group rec.arts.int-fiction. The Academy of Interactive Arts & Sciences lists his later work on multimedia services at Ucentric, a medical advice system at Gensym and planning tools for the US Air Force at BAE Systems. In February 2013 he and Blank received the Academy’s Pioneer Award, the first pair to receive it together, and in 2014 Lebling gave a “Classic Game Postmortem” of Zork at the Game Developers Conference.
Released source code
In April 2019 the archivist Jason Scott put the source code of Infocom’s games on GitHub, among them Lebling’s Starcross, Enchanter, Suspect, Spellbreaker, The Lurking Horror and Shogun, written in Infocom’s Zork Implementation Language. The repositories state no licence for those games. The Zork I, II and III sources were released under the MIT licence by Microsoft, Activision’s owner, in November 2025 (see Zork).
Sources
- “From Zork to Zero: The Infocom Story”, Retro Gamer issue 10, 2004: Lebling’s political science degree; the Dynamic Modelling Group; the founders; the first board of directors; Anderson and Lebling’s proposal to sell Zork; the release timeline; Steve Meretzky’s favourite game.
- Sean Masterson, “Four Minds Forever Voyaging”, interview with Dave Lebling, Zzap!64 issue 13, May 1986, pp. 42–43: Adventure and Zork; the founding of Infocom; the list of his games; Starcross, Clarke and Niven; Enchanter, magic and Earthsea; Sorcerer; Spellbreaker and the missing 5K; Suspect as the hardest to write.
- “Infocom special”, Your Computer, March 1987, pp. 36–37: the Dynamic Modelling Group’s maze game and Lebling’s part in it; Lebling’s parser; the grues; the boundary of about 100 locations for Zork I.
- Interviews with Marc Blank, Dave Lebling and others, PC Player (Germany), April 1999, pp. 148–149: the first test game; the golden canary; staying in Massachusetts after 1989; Avid Technology and AvidNews; hobbyist text adventures.
- Tim Anderson and Stu Galley, “The History of Zork”, The New Zork Times (Infocom), 1985 (web): the parser, the grue, fighting and the thief. https://ifarchive.org/if-archive/infocom/articles/NZT-Zorkhistory.txt
- P. David Lebling, “Zork and the Future of Computerized Fantasy Simulations”, BYTE vol. 5 no. 12, December 1980, pp. 172 onward.
- Computer Gaming World issue 88, November 1991: Infocom’s founding date; the move of development to the West Coast in 1989 and “only a label”.
- Computer Gaming World issue 6, 1982, “Hobby & Industry News”: Starcross announced for October or November.
- Computer Gaming World issue 11, 1983: Enchanter, co-authored by Blank and Lebling, due in September.
- Ray Berube, review of Suspect, ANALOG Computing issue 29, April 1985, p. 47: the plot, Lebling’s description, the Starcross box.
- Infocom advertisement, COMPUTE! issue 55, December 1984: Suspect, “our newest mystery thriller”.
- Computer Gaming World issue 21, April 1985, p. 30: “the Master of the Purple Prose”.
- Review of Spellbreaker, COMPUTE!’s Gazette issue 33, March 1986, pp. 56–57.
- Computer Gaming World issue 39, August–September 1987, pp. 7 and 46: The Lurking Horror.
- Visit to Infocom, Commodore Magazine, January 1988, pp. 72–73: Lebling’s design method, the peach tree, the plastic bug, his remark on testing.
- Computer Gaming World issue 51, September 1988, p. 20: Shogun announced, designed by Lebling.
- Review of James Clavell’s Shogun, Computer Gaming World issue 62, August 1989, p. 12.
- Academy of Interactive Arts & Sciences, special award page for Dave Lebling (web, secondary): Maze, Zork and the grue, his later employers. https://www.interactive.org/special_awards/details.asp?idSpecialAwards=26
- “Infocom founders to be honored at D.I.C.E. Awards”, Game Developer, 19 December 2012 (web, secondary): the Pioneer Award and “the first pair to receive the award together”. https://www.gamedeveloper.com/business/infocom-founders-to-be-honored-at-d-i-c-e-awards
- GDC Vault, Dave Lebling, “Classic Game Postmortem: Zork”, Game Developers Conference 2014 (web, secondary). https://www.gdcvault.com/play/1020612/Classic-Game-Postmortem
- “The Source Code For All Infocom Text Adventure Classics Has Been Released”, Slashdot, 18 April 2019 (web, secondary): Jason Scott’s upload. https://games.slashdot.org/story/19/04/18/2132228/the-source-code-for-all-infocom-text-adventure-classics-has-been-released
- historicalsource on GitHub, repositories starcross, enchanter, suspect, spellbreaker, lurkinghorror and shogun, created April 2019 (web). https://github.com/historicalsource