
There are many libraries in NYC that have excellent collections of Hebrew books. But to access some of them you have to be a student, like Colombia University and NYU. At the Jewish Theological Seminary (JTS) a person can enter to the library, but cannot take out books unless he is a student or becomes a member of the library by paying $360 a year.
The best, easiest and cheapest way to get books in Hebrew is by using the New York Public Library (NYPL). The NYPL has the largest collection of Hebrew fiction books in NYC. The library also has Hebrew books for babies and children. And it is free, you just need to get a library card. There are many branches to NYPL; you can order books on the library website at http://www.nypl.org/ and have the books sent the branch closest to you.
I don't know a lot about the Brooklyn Public Library and the Queens Public Library. I would be happy if someone can let me know about their books in Hebrew.

