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 a storybook open up that can be read in the Library. The first time a new chapter is unlocked, Princess Rosalina will be in the Library to read to Mario and the Lumas. Afterwards, Mario can revisit the Library to reread the story at his leisure.

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