Gary Gygax

Founding father of fantasy computer games and co-creator of Dungeons & Dragons

The father of role-playing games, Gary Gygax, who has died aged 69 after being diagnosed with an abdominal aortic aneurysm, was one of America's most talented writers and game designers. Best known for his role in creating gaming history's most popular fantasy role-playing game, Dungeons & Dragons (D&D), first published in 1974, Gygax also founded the publishing company Tactical Studies Rules (TSR).

Still active in the gaming community until his death, Gygax wrote a series of fantasy novels, periodicals and short stories throughout his life and inspired generations of gamers worldwide to follow a career in the industry, taking his ideas forward into the era of personal computers. In 1966 he helped to create the International Federation of Wargamers, an organisation made up of different war-gaming clubs which promoted medieval interests and served as a meeting ground for international wargamers to share ideas.

Gygax began his career by bringing 20 people together in the basement of his home in 1967. Later to be known as Gen Con 0, this meeting gave birth to what is now the world's largest annual hobby-game gathering, the Gen Con Gaming Convention - last year 26,000 people attended. At the original event, Gygax encountered Brian Blume and designer Dave Arneson, who later helped him create and work on D&D. In 1971 Gygax created his own miniature war game called Chainmail, which would later serve as the blueprint for D&D.

Gygax was born in Chicago, Illinois. His father was a Swiss immigrant. At the age of five, Gygax began playing pinochle (a bezique-related card game) and chess with a dedicated passion, which led to his discovery of science fiction.

In 1953 Gygax began playing miniature war games with longtime friend Don Kaye, who would later help him start TSR. At that stage, Gygax became particularly interested in the game Gettysburg, which he ordered from an Avalon Hill company. He then began ordering blank hexagon mapping sheets so that he could create his own games, and soon was looking for innovative ways to do so - he introduced the use of dice of all five platonic solid shapes in addition to the common dice.

Gygax and Kaye founded TSR in 1973 and published the first version of D&D the following year. Gygax drew on the work of fantasy authors Robert E Howard, L Sprague de Camp and Fritz Leiber when creating the game. Not dependent on a board, it captured players' imaginations by introducing a dimension of dragons, wizards, trolls, dwarves, goblins and elves to quests in search of treasure or to defeat the forces of evil. All this was achieved with just graph paper, pencils, the polygonal dice and a set of complex rules.

Often there was no obvious winner to the open-ended, and highly sociable, activity. While Gygax accepted the inevitability of the later electronic and online versions, he felt that computer graphics dulled the experience. "Your imagination is not there the same way it is when you're actually together with a group of people."

The first hand-assembled print run of 1,000 copies sold out within the first nine months and, in the same year, Gygax hired Tim Kask to assist in the transition of the magazine the Strategic Review into the fantasy periodical, the Dragon, with Gygax as author and later columnist. But Gygax's history with TSR was not altogether a happy one.

After Kaye's death in 1976, his widow sold her shares to Gygax, who was now in control of the whole company and created TSR Hobbies Inc. Gygax soon found himself in financial difficulties and was forced to sell it to Blume and his brother Kevin, who would own two-thirds of the company by late 1976.

In 1977 a new version of D&D was created, Advanced Dungeons & Dragons, a game whose rules were not compatible with those of the original and, as a result, new product lines and expansions at TSR took place. Gygax left the company in 1985, citing his increased concern at being sidelined from running the business. He began work on a CBS cartoon series version of D&D.

In 1995 Gygax started developing a new role-playing game, originally intended for computers: it was released in 1999 as Lejendary Adventure. A key goal of its design was to keep the gaming rules as simple as possible. Gygax felt that role-playing games were becoming discouragingly complex to new users.

In 2005, he returned to work on D&D with his involvement in the creation of Castles & Crusades with Troll Lord Games. Gygax became an icon to gamers, making several television appearances as himself in episodes of Futurama and Code Monkeys and participating in discussions on role-playing-related message boards.

From the age of eight until his death, he lived in Lake Geneva, Wisconsin. In 1987, he married his second wife, Gail Carpenter. She survives him, as do three sons and three daughters.

· Ernest Gary Gygax, writer and game designer, born July 27 1938; died March 4 2008