The Library can only be reached by "teleporting" through a sewer from Stormhold on level 2.
After entering Stormhold, you pass straight through the entrance hall, through the set of double doors and into a chamber with four doors (two either side).
Make a left at the first 'T' intersection, ( -54, 5, -111 ) Copy/waypoint -54.30, 5.00, -110.69.
Make a right at the second 'T' intersection, ( -55, 5, -119 ) Copy/waypoint -55.20, 5.00, -118.62.
Cross over the damaged section of hallway at ( -77, 5, -119 ) Copy/waypoint -76.79, 5.00, -119.14.
Turn right at the third 'T' intersection, ( -104, 5, -122 ) Copy/waypoint -103.55, 4.99, -122.23 . The wooden door on the left leads to the Barracks and Captina Guard Hess' room, which is a dead-end for this venture.
Turn left at the fourth 'T' intersection, ( -104, 5, -111 ) Copy/waypoint -103.80, 4.99, -111.11. The right is a blocked tunnel.
Going forward, the tunnel will curve around to the right.
At ( -133, 5, -96 ) Copy/waypoint -132.89, 5.00, -96.08, turn left and go through the wooden door.
This is the entrance to the Claymore stairway - go down the stair to the bottom which is now the second level, the floor where the sewer-grate is.
The sewer grate is at ( 5, -26, -121 ) Copy/waypoint 5, -26, -121 and you can now reliably follow the Waypoint wisp all the way to sewer-grate room without getting lost. It's a big room with a triple-fish statue, in the northwest of the second level, that contains zombies, white oozes, root horrors and Qelinatias the Scion of Pain.
The maps provided by EQ2MAP for this part of the dungeon are confusing, as the red bordered hallways don't connect to the black bordered ones as they are underneath those.
After you get into the library, you'll also find there is a door at ( -118, -32, -182 ) Copy/waypoint -118, -32, -182. This door leads out to the northeastern beach in Antonica. After you unlock and exit this door for the first time you can forever use it as entrance to Stormhold and as an exit to Antonica.