The Library can only be reached by "teleporting" through a sewer from Stormhold.
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). Take the second right hand door, make a left at the 'T', follow the hall right, then over the broken section of hall. Down this hallway, behind one of the doors on the left near the end will be the entrance to the Claymore stairway. This will lead you down to the second level, where the sewer is. The sewer grate is on the floor of the big room 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 ) /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.