Intelligence is a third attribute that determines magical ability — a high IQ score allows the use of more varied and powerful spells.

Released as an 80-page, 81⁄2 × 11 saddle-stitched book, In the Labyrinth: Game Masters' Campaign and Adventure Guide adds a role-playing system and fantasy-world background to The Fantasy Trip.

However, Jackson did not like either the long and complex rules nor the character creation system with its randomly determined attributes.

[1] Metagaming Concepts had just started publishing their MicroGame line, small and simple games packaged in either a ziplock bag or a thin plastic case.

MicroGame #3, published in 1977, was the first part of Jackson's new RPG, a game titled The Fantasy Trip: Melee.

Although Melee and Wizard established combat and magic rules, Jackson wanted produce a complete RPG.

[2] After Howard made changes to the game, Jackson was not shown the final proofs, and Howard published The Fantasy Trip RPG as four separate books: Advanced Melee; Advanced Wizard; In the Labyrinth (a gamemaster's guide); and an adventure titled Tollenkar's Lair.

[3] The Thieves' World licensed campaign setting, published by Chaosium in 1981, also included character statistics and notes for use with TFT.

Two Metagaming-published magazines, The Space Gamer and Interplay featured TFT material, including designer notes, setting expansions, and alternate rules.

Jackson tried to purchase the rights to The Fantasy Trip, but Thompson's asking price of $250,000 was much too high, and TFT went out of print.

In 1988, Hobby Japan released a Japanese-language edition of TFT under the name Phantom Unicorn Quest (幻のユニコーンクエスト, Maboroshi no Yuniko-Nkuesuto).

[6] In July 2018, Steve Jackson Games launched a Kickstarter campaign to reissue Melee, Wizard, and a TFT Legacy Edition boxed set with the expanded In the Labyrinth rules, among other materials.

[8] On December 26, 2017, Steve Jackson announced he had re-acquired the rights for the TFT products he authored for Metagaming, specifically Melee, Wizard, Death Test, Death Test 2, Advanced Melee, Advanced Wizard, In the Labyrinth, and Tollenkar's Lair.

On July 23, 2018, Steve Jackson Games opened a Kickstarter campaign for The Fantasy Trip Legacy Edition including updated versions of all the works reclaimed from Metagaming; the new version of In the Labyrinth incorporated Advanced Melee and Advanced Wizard, as originally envisioned by Jackson.

A number of tribute and fan websites preserved and expanded TFT over the years, including a long-running E-mail discussion list archived at tft.brainiac.com.

Heroes & Other Worlds similarly builds on TFT, albeit with greater deviation from the original rules.