The Library is a location accessible only by talking to the old man with a ship on Route 9. It appears to be an ancient, partially-ruined library of some kinds, occupied by various Team Wack and Juvite grunts.
The Library is a strictly optional area, that is done only for the purpose of encountering a new Pokemon: Bookly, which can be found at the end of the maze of grunts.
Items[]
TM04 (Calm Mind): Southwest corner.
TM03 (Psyshock): Southeast corner.
Heart Scale x2: East of Team Juvite Grernt, and northwest of Team Juvite Gryynt.
TM151 (Paper Orb): Northwest of the first passageway.