The Elder Scrolls IV: Oblivion Guide
The Mages Guild is one of the four joinable guilds in Oblivion. To join, visit the Mages guild hall in Anvil, Bravil, Bruma, Cheydinhal, Chorrol, Leyawiin or Skingrad, and speak to the guild member in charge of recruitment. Speak to anyone other than this character about joining the Mages Guild to be directed to the right person.
Becoming a member of the Mages Guild yields several benefits. Most importantly, after completing the string of recommendation quests needed to become a full member of the guild, you'll then be able to access Arcane University in the Imperial City. The enchantment altars in the university can be used to create new spells and imbue weapons with magic properties.
To become a full member of the guild, you'll first have to complete the 'Join the Mages Guild' quest. To complete this quest, you must visit each Mages Guild hall in Cyrodiil, speak to the hall leader there, and select the 'Recommendation' dialogue option. Then, complete the small quest given to you by the leader to receive a recommendation from that hall. The seven recommendation quests do not need to be completed in a certain order.
This section is broken down into the following chapters:
A Mage's Staff
Liberation or Apprehension
Information at a Price
A Plot Revealed
The Bloodworm Helm
The Necromancer's Amulet
Confront the King