The dominion of Lady Friday; now in possesion of the New Architect. The Middle House was the fifth demense that Arthur gained control of as the Rightful Heir. The Middle House, alike its Lower and Upper House counterparts manage the administration of the records.
The Middle House is split into three parts, each separate but with passage between them. They are known as the Top Shelf, the Middle of Middle and the Lower Shelf (?). Each part of the Middle House deals with restoration and improvement of records, like the Top Shelf is home to the Guild of Binding and Restoration, while the Lower Shelf employs itself with activities such as Guilding.
The Extremely Grand Canal stretches through all three shelves and provides passage between the shelves for those who cannot use an elevator. It rises up to the ceiling of the Lower Shelf and the Middle of Middle through the two Skygates which can be opened and closed as necessary. The water is Textually Charged, meaning that anything in the water with text will float while anything else will sink. It is for this reason that the Paper Pushers who live on the Canal wear clothes comprised of documents. The Canal also has many different currents to allow travellers to move in opposite direction simultaneously.
The Lower Shelf appears to have cold climate, the Middle of Middle has a more moderate one and the Top Shelf has one decribed as close to tropical.
The sun on the Lower Shelf appears to be in a state of disrepair as it recently stuff causing a period of perpetual twilight. From the comments of Fred Initial Numbers Gold, this has happened before.
The Top Shelf is also the location of Friday's Scriptorium and the eeyrie of the Winged Servants Of The Night