Writer:	John O'Bryan
Director:	Giancarlo Volpe
Star:	Jessie Flower (Toph),  Zach Tyler Eisen (Aang),  Jack DeSena (Sokka),  Mae Whitman (Katara),  Dee Bradley Baker (Appa/Momo/Various Others)
Guest Star:	Hector Elizondo (Wan Shi Tong),  Raphael Sbarge (Professor Zei)

Translations: - The writing on Professor Zei's map means 'Wan Shi Tong's Mysterious Library'
-The parchment documenting the Fire Nation's Darkest Day means 'the 9th day of the 8th month of the Cultivate Rule Dragon Year was the darkest day in Fire Nation history' (edit) Character Debuts: Wan Shi Tong, Professor Zei (edit) Creature Debut: Wan Shi Tong. (edit) Hero Debut: Professor Zei (edit) Based on Wan Shi Tong's statement, there are at least three styles of waterbending: Northern Water, Southern Water, and Foggy Swamp style. Katara's own style (and by extention Aang's) is obviously Northern Water, having been trained by Master Pakku. The waterbenders from the episode The Swamp are hereby identified as the Foggy Swamp Tribe, whose style has also been displayed. (edit)

Professor Zei: (to Wan Shi Tong) Hello. I'm Professor Zei, Head of Anthropology at Ba Sing Se University.
Wan Shi Tong: You should leave the way you came, unless you want to become a stuffed head of anthropology. (points out his collection of animal heads on a nearby pillar) (edit) Sokka: That fox thing went through a window. I say we climb up there and give it a look.
Toph: I say you guys go ahead without me.
Katara: You got something against library's?
Toph: I've held books before, and I gotta tell you, they don't exactly do it for me.
Katara: Oh right, sorry.
Toph: Let me know if they have something you can listen to. (edit) Toph: I can see by feeling the vibrations on the earth, but the sand in this desert is so soft and shifty that it makes it all look fuzzy. (Appa groans apparently angry) Not that there is anything wrong with fuzzy things. (edit) Aang: Why are we doing this?
Sokka: Because if this calendar can tell us about eclipses in the past, then maybe it can project when the next one will be.
Aang: You can’t possibly check every single date.
Sokka: I don’t have to. We just have to check every date before Sozin’s comet arrives, because after that…Well, try not to think about that.
(edit) Professor Zei: Oh, it is. According to legend, it was built by the great knowledge spirit, Wan Shi Tong, with the help of his foxy knowledge seekers.
Sokka: Oh, so this spirit has attractive assistants, huh?
Katara: I think he means they look like actual foxes, Sokka.
Professor Zei: You're both right, hansom little creatures. (edit)

The bag Sokka bought in the Library was again seen here and used to store papers stolen from the library. (edit) When they take Appa away, the Library's Tower was short from sinking. After Toph said "I'm sorry Appa," the tower appeared taller as the Sandbenders take Appa away. (edit) When we are shown Katara climbing down the rope, the white part of her right sleeve turns the same color as her sleeve. (edit) When Katara is hiding behind a bookcase from Wan Shi Tong with Momo in her arms, the white of her collar is blue like her robe. (edit) When they reach the library, Sokka is seen climbing up the rope first, yet when they are inside the library, the professor is seen sliding down the rope first and Sokka is last. (edit)

The "Lion-Turtle thing" Aang describes appeared as a statue behind him while he was performing the Air Scooter move in the intro sequence of the unaired pilot. (edit) The calendar in Wan Shi Tong's library seems to be based on the Antikythera Mechanism or a early astronomical clock. The Antikythera Mechanism was an ancient mechanical analog computer designed to calculate astronomical positions. (edit) It is unclear as to what kind of owl Wan Shi Tong is. He has qualities of several different owls, including the eyespots of a Pygmy and the face of a Barn. (edit) Wan Shi Tong's library looks a lot like the Taj Mahal in India. (edit) Professor Zei's name comes from a character meaning "thief" or "robber" in traditional Chinese. This is actually a reference to the fact that this is what archaeologists were considered to be before anthropology was established as a semi-official social-science. (edit)