Claudia's mother Rioko Kishi is the head librarian and sometimes when the Baby Sitters Club members go to the library, Mrs. Kishi directs them to the books they are looking for or they say 'hi' to her.
The library has many books, but it doesn't have Claudia's favorites: Nancy Drew books.
As revealed in Book #17 Mary Anne's Bad Luck Mystery, the library has only been open for about 8 or 9 years.
The library has a section of books on Spells and Witchcraft. The library also keeps a file of all of the local authors and illustrators that live in the area, including Henrietta Hayes, one of Mallory's favorite authors. The library also has a meeting room to host a variety of events, such as the slapstick film festival mentioned in Book #19 Claudia and the Bad Joke.
The first time that a BSC member went to the library was in Book #6 Kristy's Big Day, when one of the members took her charges to story time at the library.
The second time a Baby Sitters Club member went to the Stoneybrook Public Library was in Book #17 Mary Anne's Bad Luck Mystery when the Baby Sitters Club members at the time (Mary Anne, Dawn, Claudia, Kristy, Mallory, and Jessi) went to the library to check out books on Witchcraft and Spells.
Not many librarians besides Mrs. Kishi have been at the library when the BSC members are there.