Thieves Guild

Addhiranirr, one of the NPCs you will meet in the Main Quest, has the best description of the Thieves Guild that I have seen. "It is just is a social club. We like the finer things in life. Those who join this club, they must know how to get the finer things in life." The Thieves Guild does not have Guild Halls, so they tend to hang out in cornerclubs.

As the new kid on the block, the Thieves Guild is having trouble with the old kid on the block, the Camonna Tong. Consequently you will find your reception from Camonna Tong members to be somewhat less than warm. There is a somewhat overarching storyline through the Thieves Guild quests involving the Guild defending itself from the Cammona Tong. It's not as clearly spelled out as, for example, the Mages Guild vs. Necromancers storyline in "Oblivion", but it's there. You can play both sides, to a certain extent, by following both the Thieves Guild and Fighters Guild questlines at the same time.

Members of factions receive different types of welcomes from members of other factions, depending on how they get along. The formula is (Faction Reaction * 5)*(0.5 +(Faction Rank *0.5)). In plain terms, this means that as you attain higher ranks in your faction, people with negative modifiers will like you less and people with positive modifiers will like you more. This does not mean that everyone will start attacking you on sight, nor does it mean that they are going to fall all over themselves to be helpful. It does, however, modify their initial disposition toward you. This initial disposition will be further modified by your Personality, your overall reputation, your Criminal Status, whether or not you are Diseased, what kinds of favors you have done for the faction you're dealing with, etc. The other person may wind up liking you a lot or not liking you at all, but your faction and rank can impose a serious modifier.

Reactions to Other Factions
Hated Enemy
Beloved Ally (+3)
Camonna Tong Ashlanders Temple
House Hlaalu
House Redoran
Imperial Legion
House Telvanni
Morag Tong
Mages Guild
Imperial Cult
  Thieves Guild

Advancement within the Thieves Guild will depend upon your skill level in three of the following skills:

Light Armor

Short Blade

Thieves Guild rank structure:

Rank Agility Personality One required Skill at Two other required Skills at Minimum Faction Reputation
1 - Toad 30 30 0 0 0
2 - Wet Ear 30 30 10 0 5
3 - Footpad 30 30 20 0 10
4 - Blackcap 30 30 30 5 20
5 - Operative 30 30 40 10 30
6 - Bandit 31 31 50 15 45
7 - Captain 32 32 60 20 60
8 - Ringleader 33 33 70 25 80
9 - Mastermind 34 34 80 30 100
10 - Master Thief 35 35 90 35 125

Of course, these promotions don't come just based on your skills. You must perform quests to gain reputation and rank within the Thieves Guild. You will typically receive 5 points of faction reputation for each successfully completed quest. Just ask about "jobs" to anyone who has it in their conversation threads. The Thieves Guild quest givers are, in no particular order:

Typically, each rank requires two or three successfully completed quests in addition to the minimum stat and skills requirements.

Stacey has two sets of quests to offer. The first set, four Thieves Guild "jobs", require that you be at least Rank 7 in the Guild before he will offer them and Rank 8 for the last two. The second set, the Bal Molagmer quests, should be available to you at any rank.