The Mystic Archives is the most extensive library in Cyrodiil. The archives are run by Tar-Meena, with frequent visitor Boderi Farano helping out. The actual archives can be found upstairs, but there are many books on the main floor as well. The stairs in the northwest corner lead up to the upper level.
A desk sits right beside the entrance and contains clutter, and a stool with a copy of Necromancers Moon on it sits close by. Behind the desk is a bookshelf holding a few books, including Modern Heretics, On Oblivion, Magic from the Sky, and Five Songs of King Wulfharth. Near the foot of the stairs lies a clutter desk. Next to the desk a cupboard containing clutter can be found with a novice alembic on top of it. In the corner on the same side of the cupboard sit three clutter barrels. Two unlocked display cases can be found in the room, each containing a book: the one on the east wall holds the skill book Mannimarco, King of Worms, while the one on the south wall holds a copy of Fighters Guild History, 1st Ed. The bookcase on the east wall holds a few books, including Cleansing of the Fane, Dwemer History and Culture, and the skill book Response to Bero's Speech. All of the containers in this room respawn.
Mystic Archives Upper Level
The upper level of the Mystic Archives contains an impressive collection of books from across Tamriel. It has the appearance of a typical library. On the north wall beside the door is a desk which holds two empty common soul gems and two samples of bonemeal, and contains only clutter. In the northwest corner of the room a small reading area holds a chest of drawers that contains more clutter and a table that holds a copy of Children of the Sky. On the chest of drawers, two empty common soul gems and samples of bonemeal, ogre's teeth, and nightshade can be found. A desk in an alcove on the west wall holds more clutter. A clutter barrel sits in the southwest corner next to a display case that holds three books; Hanging Gardens, The Wilds Elves, and the Conjuration skill book Liminal Bridges.
On the south wall, a display case between two large bookshelves holds a copy of Spirit of the Daedra. The bookshelf on the right holds six bottles of Surilie Brothers Wine, a clutter sack, four novice retorts, a novice alembic, and several books including The Third Door and the Illusion skill book The Argonian Account, Book 3. The bookshelf on the left holds a novice retort and several more books including Magic from the Sky and three copies of The Firmament.
Two clutter barrels sit in the southeast corner, next to the third bookshelf. It holds an alembic, a calcinator, a retort, and several notable books including Hanging Gardens and The Last King of the Ayleids. With the Knights of the Nine official plug-in, The Adabal-a, The Knights of the Nine, and Shezarr and the Divines are also found on the shelves, as well as all eight volumes of The Song of Pelinal along with a second copy of volume seven. Two clutter sacks sit between the bookshelf and the door.
In the center of the room, a small table surrounded by chairs is arranged. A small stand holds a plate with two apples and a pear, while the table holds two more apples, a loaf of bread, two bottles of cheap wine, and a seventh bottle of Surilie Brothers Wine. The three sacks are the only containers that do not respawn.
Elder Scrolls Wikia entry on this location can be found here.