1st Edition: 1988 - 1989

Codex Issue Details
-Rulebook + White Dwarf #109 Errata.

-Reavers and Warhound Rules - Page 77.

-Errata - Page 78.

-Rules for Vehicles in Adeptus Titanicus - Page 11.

-Eldar Phantom Titans: Shade & Spectre Variants - Page 60.

-Vehicle Rules: Eldar Walkers, Jet bikes, Artillery, etc - Page 66.

-Infantry Rules: Space Marine Infantry - Page 31.

-Chain Fist! Advanced rules for Combat - Page 51.

-Rules for Craters - Page 67.

-Conqueror! Robot Rules, Data cards and Army List. - Page 68.

-Death Blow! Advanced Damage Rule. - Page 25.

-Rulebook.

-Expansion Rules for epic battles.

-Adds the forces of the Orks and Eldar as well as containing rules for more Imperial Titans, Dreadnoughts and Robots.

-Updated rules and Errata.

Utilities
Adeptus Titanicus Reference sheets
Titan Data Cards

2nd Edition: 1991 - 1995

Codex Issue Details
-Rulebook.
-Armies of the Imperium was an expansion box set for 2nd Edition Epic, giving more options and units to Imperial players..
-Eldar and Chaos Rules, Army lists + Background Info.
-Ork and Squat Rules, Army lists + Background Info.
-New General Rules +
-Tzeentch.
-Epic Personalities like Commissar Yarrick.
-Imperial Titan Weapons.
-Gargants.
-RuleBook: Titan Legions was the second boxed set released for the second edition of the Epic game system.
-Codex: Codex Titanicus is an army and background book for the Titan Legions (game)
-Tyranid Rules, Army lists + Background Info.
-Eldar.
-Knights.
-Adeptus Mechanicus.
-Chaos.
-Squats.
-Imperial.
-Airpower.

3rd Edition: 1997 - 2002

Codex Issue Details
-Rulebook.
-Chaos, Eldar, Hive Fleet, Imperial Guard, Orks, Space Marines.
-Craftworld Eldar, Dark Eldar, Eldar Corsairs, Exodites, Imperial Guard, Necrons, Orks, Sisterhood Order Militant, Space Marines, Squats and Tau.
-Picking Scenarios,Setting up and more, also Painting guides, Making Terrain, etc.
-A break down of whats in each issue + if it is offical or not.
-Army rules for the Adeptus Arbites, Adeptus Mechanicus, Daemonic Legions and Squats, rules amendments, new missions and tactics for flyers, Titan weaponry and upgrades, campaign rules.
-Army rules for non-codex Astartes, Deathwing, Blood Angels Death Company, War Engines battle honours, Abominatus Emperor-class Chaos titan, Fate cards, Last Stand at Glazers Creek scenario.
-Army rules for the Ordo Malleus and Genestealer Cults, new units and alternative detachments for the Imperial Guard, Chaos and Orks, rules for the Land Raider patterns, Crash & Burn scenario, Pegasus-class navy assault transport.
-Additional rules for Ork Clans, Coal Mountain scenario, Tyranids scenarios, Imperial Guard medics, engineers, support vehicles and tunnellers, rules for fortifications.
-This is a combination of the new Rules, Updates and Titan Data sheets.
-The rules for Adeptus Titanicus II (AT2).
-The AT2 rules & titan sheets for the Warhound, Reaver, Warlord Titans, Emperor Class Imperator and Warmonger Titans.
-AT2 rules & sheets for the Orks:- Skullhamma, Gibletgrinda Battle Fortresses, Gargants, Great Gargants, and Mega Gargants.
-AT2 rules & sheets for the Baneblade, Shadowsword, and Leviathan.
-Adeptus Titanicus II Errata.
-Rules for Many new Ork Units.
-Jervis relents and decides to make Epic 40k and AT2 into two separate games.
-AT2 rules & sheets for the Eldar Units:- Revenant and Phantom Titans, as well as Cobra and Scorpions tanks.
-AT2 rules & sheets for the Tyranids. Includes Hierodule, Hierophant, and Dominatrix.
-New warhead rules for Deathstrike Missiles.
-AT2 rules & sheets for Chaos:- Chaos Warhound, Chaos Reaver Titan, Chaos Warlord Titan, Banelord, Subjugator, Questor, Lord of Battle, and Plague Tower.
-Lightning Fighters, Abominatus in Adeptus Titanicus, Experimental Rules: Fortifications, Building Terrain Boards.
-Warmonger Titan rules for Epic 40k.
-Official AT2 Adeptus Titanicus Rules Update and Q&A.
-Ork-o-Nowa (A massive Ork beach assault by Kieth Wilson and friends),Adeptus Titanicus Rules Update
-TAU Rules Part 1.
-New rules for Deathstrike Missile warheads and artillery.
-TAU Rules Part 2.
Fan made
-Fan made; it combines everything into 1 place.
-Fan made; Same rules, but easier to use! Website : thehobby website for latest rules.
Utilities
-Editable Detachment sheet.

4th Edition: 2003 - 2009

Rulebook + Errata.
Rulebook: Eldar, Imperial and The Feral Ork troops.
Fan Made Rulebook, widly excepted as main ruleset today.

Useful links

miniwars.co.uk 3rd party Models and Armageddon rules

EpicUK army-lists