It is a large collection of evidence that Dewey and his "comrade", most likely Kit Snicket, has collected over the years that can send all villains to jail. Simply put, it contains information about every person, place, thing and event that has had association with V.F.D. According to Dewey, all the information is in underwater rooms organised like "a mirror image of the hotel itself." Judging by that fact, the library is most likely the best chance for persecuting the fire-starting side of V.F.D.
Although the hotel is destroyed, Lemony mentions that the underwater library has remained safe all these years.
- 27 cakes that Count Olaf has stolen
- It is also known to have an entry on an interpretation of sausages that went horribly wrong, having destroyed a bathyscape (all of which was an huge accident on Lemony Snicket's part when he mistook the sausages to say K instead of R).
- An interpretation of the law, also described in The Penultimate Peril, that went horribly wrong.