Published in Maximum Tech, Revised Edition.
Rules Level 1
Published in BattleTech Fourth Edition, and generally dealt with the Technology Level first introduced in the Age of War along with one piece of equipment developed in the Succession Wars era. Rules Level 1 equipment is on the referenced page.
Rules Level 2
Was Published in BattleTech Master Rules, and dealt with Standard and Advanced Rules and/or Special Case Rules. This book included Age of War and Succession Wars era equipment dealt within Rules Level 1 as well as the Technology first introduced in Technical Readout: 2750, Technical Readout: 3050, Field Manual: Draconis Combine, Field Manual: Free Worlds League, Field Manual: Warden Clans, Field Manual: Crusader Clans, Field Manual: Capellan Confederation, Field Manual: Federated Suns, Field Manual: Lyran Alliance and Field Manual: Periphery. Rules Level 2 equipment is listed on the referenced page.
The Game Play and Construction Rules dealt with in this book constitute the level of game play that most BattleTech players experienced.
Rules Level 3
Published in Maximum Tech, Tactical Handbook, and the official MechForce North America Magazines (that FASA exercised some oversite over), as well as the MechForce Worldwide Magazines (that FASA never exercised creative control over).Rules level Three constituted Rules expansions added to increase the realism of the BattleTech Game but were too complex for standard play.