Library (Super Mario Galaxy)

The Library is an area of the Comet Observatory in Super Mario Galaxy. While not technically a Dome, it can be entered. As the player collects Power Stars, chapters of Rosalina's Storybook, open up that can be read in the Library. The first time a new chapter is unlocked, Rosalina will be in the Library to read to Mario/Luigi and the Lumas. Afterwards, Mario/Luigi can revisit the Library to reread the story at his leisure. The Library makes a quick appearance in the end of Super Mario Galaxy 2 where Rosalina is reading to the Lumas about the game itself and the Green Power Stars.

The book, while it is never explicitly said, tells the story of Rosalina and how she came to live on the Comet Observatory with the Lumas.