Sarna.net is a good place to start
I haven't gotten through MW2 yet (still trying to get it to play nicely with Dosbox and not freeze on the second mission!), so I don't know exactly what it covers, but MW3's storyline would make sense if you read up on Operation Bulldog, Operation Damocles (MW3's story) and the Great Refusal (that's the battle at Strana Mechty mentioned at the end).
If you want to know what was meant by "fighting by clan rules" in the MW3 ending, understand this: The clans invaded (with all in agreement except Clan Wolf, who did not want to invade), and brought with them vastly more sophisticated technology, because the Inner Sphere had lost much of their technology by ransacking their civilization with centuries of warfare (see the Succession Wars), loosing much of the technology of the body that
did exist, called the Star League, technology that the clans retained much of, because they had split off centuries earlier (Read the MW3 instruction manual for a real brief overview). What they didn't have was the first clue about how to fight a war (*dons flame suit*). They basically came in with these notions of honorable combat, expecting the IS to play by all this etiquette of theirs in war, and the Inner Sphere went "WHOA, WHOA, WHOA, now hold on, we didn't ASK you to invade our worlds, and we'll fight you back as we damn well please", and having spent centuries fighting
real wars, not structured bouts of glorified honor duels, the IS may not have had tech, but they
did have some clue of how to make an enemy suffer, and that's what they did, bogging down many of the clans, and inflicting considerable casualties, still losing overall at first because of tech disadvantages, but eventually getting their footing, and, despite inferior tech and supposedly inferior pilots, eventually beginning to turn that trend back on the Clans (see the Battle of Luthien). Comstar (another power you should read up on) actively cooperated with the clans at first, seeing them as a way to crush the successor states like the Fed Suns and Lyrans, until, as I understand it, they realized what the clans were, and went and kicked their rear ends at the Battle of Tukayyid, at which point the tide
really started turning against the clans. Then the clans agreed to a truce, another egregious mistake on their part, because it allowed the IS time to sit down, start sorting through some clan tech, and at least
start to close the tech gap a little bit (as if the clans weren't doing badly enough by mid 3052
with their tech advantage!). So by the time Operation Bulldog started against Smoke Jaguar and the IS really began fighting back and pushing the clans back, you started seeing a lot of new IS designs get fielded. The rest is history, ending with the clan defeat on Strana Mechty, an invitation for the clans to become friends with the IS, and the opening of a new chapter in history with tons of new problems to solve.
Mechwarrior 4 covers the FedCom civil war between Federated Suns and Lyran Commonwealth (who had briefly joined as the Federated Commonwealth), two powers on opposite sides of the galaxy (the Federated Suns under Davion, and the Lyrans under Steiner). The conflict was not
necessarily as one-sided as is portrayed in the games... but not necessarily a whole lot less one-sided, morally. You can make those judgements yourself, taking the games and other material into consideration.
There's some good basic guides around too that people have been trading about, but that gives you an idea of the clan invasion and Fedcom civil war.
Basically:
-Star League exists for awhile, but breaks up (eventually creating the successor states)
-At some point amidst that, Alexandr Kerensky leads much of the military out of the Inner Sphere, and that society he founds eventually gets contorted into the Clans
-The clans are split between Wardens and Crusaders, who respectively see themselves as either the ultimate guardians or conquerors of the IS people (I don't know much about the details there, admittedly)
-After an IS vessel happens upon the clans and is capture, the clans garner data on the state of the IS, and seek to invade; Clan Wolf attempts to stop the invasion, but fails, and is made to be the tip of the sphere as punishment for their opposition (as payback for the payback, Clan Wolf ends up being way more successful than the other clans)
-The clans invade, Comstar, who doesn't like the successor states, cooperates with them, and the IS in general gets lambasted by clan tech early on. I've heard stories from friends more familiar with BT than I of single Dire Wolves (Daishis) parking on ridges, and sniping huge swaths of IS mechs who can't even return fire without first having to close way in because of the range disparity
-Comstar pulls their heads out of their rear ends eventually, and the IS goes "Oh, hey! A war! We remember how to fight these!", and the clans gets their ***** kicked
-Amidst the clan war, Fedcom is formed (3055?), but Katrina Steiner sets events into motion that begin a civil war between the Fed Suns and Lyran portions of the alliance between the two houses. The Fedcom civil war starts in 3062.
Edited by Catamount, 04 January 2012 - 09:48 AM.