Short answers, pulled from the story.
The City State of the Invincible Overlord was first published in 1976. This initial release occurred after founders Bob Bledsaw and Bill Owen were rejected as vendors at Gen Con IX and forced to sell their product from a car in the parking lot.
The dwarven fortress and town featured in the City State of the Invincible Overlord is named Thunderhold. The original 1976 edition included a massive 34 by 44 inch four-page map depicting the town with winding alleys and jumbled buildings.
The 1983 edition of the City State of the Invincible Overlord contained 96 pages. This edition notably removed the phrase Approved for use with D&D from its cover.
The Mayfair Games boxed set from 1987 to 1989 included a four-page introduction, an 80-page Map and Population book, a 32-page Background and Encounter book, and a large full-color map. The map featured the city on the front and an island campaign setting on the reverse.
The 2004 Necromancer Games edition of the City State of the Invincible Overlord was released in 2004. This edition became a 288-page hardcover book revised for the d20 system.